Sudden Cardiac Death

sudden, cardiac, death, hearth, sport, athlete, scd

What’s up ? This is THE stephane ANDRE. With my training, I’m interested in biomechanics to avoid injuries. I read « Sport Medicine Media Guide » and I learned some good stuff.

Sudden cardiac death (SCD) is an extremely rare event. The most common reason for cardiac death related to sports is the cardiomyopathy hypertrophic, an abnormal enlargement of cardiac muscle. It’s a rare heart disease that predispose a person of SCD because of physical exertion.

Commotio cordis is another reason for SCD. It’s a direct trauma to the chest at a specific moment in the cardiac cycle and this trauma triggers a dangerous arrtyhmia (abnormal rhythm) of electrical system of the heart. A commotio cordis usually arrives in sports where a blunt projectile, such as baseball ball or hockey puck, hits the athlete’s chest.

Treatment

Cardiac arrhythmias that threaten the lives of young athletes are very difficult to treat. The immediate use of AED (automated external defibrillator) can provide an advantage.

Prevent

sudden, cardiac, death, sport, hearth, athlete, scd

Unfortunately, the only way to prevent death from hypertrophic cardiomyopathy is to identify the disease and recommend the athlete avoid any strenuous activities. Cardiac ultrasound can diagnose this condition. Some experts have called for the screening of athletes with ultrasound or electrocardiograms (EKG), although this screening is controversial because of the high cost and scarcity of this condition.

However, athletes with cardiac symptoms such as dizziness, fatigue, shortness of breath in relation to physical activity, palpitations, convulsions and especially syncope (fainting) must stop the competitions and must do deeper tests.

In addition, a family history of cardiac abnormalities justifies a complete cardiac evaluation. Especially a known parent with hypertrophic cardiomyopathy or a history unexplained sudden death in a family member.

There is the creation of different forms of protection for the chest and pads, but unfortunately no method has prevented this tragic event. The rules regularly change in the sport and some times to try to avoid commotio cordis. For example in baseball and softball, it’s the limitation of the use of aluminium bat. This rule can protect the pitcher by decreasing the speed of the ball after contact with the bat. There are other rules too, such as using a softer ball and teaching players to turn their chest when the ball is hit by the bat.

Stats

  • Fortunately, SCD is extremely rare in the sport. For the majority of people do sports to cardiac benefits.
  • In young athetes, the most common causes of SCD are 25-30% hypertrophic cardiomyopathy and 20% commotio cordis.
  • Coronary artery abnormalities are the cause of 14% of SCD in athletes.
  • Marc-Vivian Foe, a Cameroonian soccer star had a sudden cardiac death during a match in 2003.

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-Steph

P.S. If you’re in Miami and you like Caribbean food, go to my cousin’s bistro to eat Haitian food, click here .

Steroids

sport injury steroids performance enhancing drug

What’s up ? This is THE stephane ANDRE. With my training, I’m interested in biomechanics to avoid injuries. I read « Sport Medicine Media Guide » and I learned some good stuff.

We regularly read in news articles, the use of anabolic steroids or performance enhancing drugs by elite athlete. But you should know that these dangerous drugs are more and more used by children in college, high-school and middle school.

What

sport injury steroids performance enhancing drug

Anabolic steroids are synthetic derivatives of testosterone. Testosterone is a male sex hormone. Steroids help to create new proteins to increase the size and strength of muscles. The body is already doing this process naturally but steroids increase the activity of this normal process. Find performance enhancing drugs in communities, gyms or internet is easy.

Steroids are consumed orally or by injection. Anabolic steroids in themselves aren’t effective. However, when they’re used at the same time with a strength training, they increase the strength in an impressive way.

Side effects

sport injury steroids performance enhancing drug side effect acne

sport injury steroids performance enhancing drug side effect acne

sport injury steroids performance enhancing drug side effect acne

Performance enhancing drugs allow an athlete to have bigger and more powerful muscles, but users may have deadly health problems. Performance enhancing drugs have several side effects that continue to work even after you stop using them. Users are also more likely to have risky behaviors such as having unsafe sex or taking illegal drugs.

Symptoms of use of anabolic steroids are :

  • Acne (often severe) visible on the face and back

  • Severe mood change such as extreme aggression or suicidal behavior

  • Premature balding, breast enlargement (gynecomastia), irreversible shrinking of testicles in boys.

  • Deeper voice, shrinking breast and clitoral enlargement in girls

  • Dangerous enlargement of the heart that can increase bad cholesterol and blood pressure.

  • Irreversible liver damage

  • In children, premature closure of the growth plates, stopping normal growth of bones.

sport injury steroids performance enhancing drug side effect gynecomastia

sport injury steroids performance enhancing drug side effect gynecomastia

sport injury steroids performance enhancing drug side effect gynecomastia

A reason to take anabolic steroids

Anabolic steroids may be advisable for people who have lost testicular function like men with a testicular tumor. They’re also advised in some type of anemia to stimulate the bone morrow.

Prevent

The true is the problems of performance enhancing drugs aren’t solely related to elite athletes. Children are also exposed to this every day. Ask kids what they know about these drugs. Ask them if they know anyone in their school class who uses these drugs. Ask them if they know the dangers of these drugs. If you think that your children or children in your family might be experiencing these drugs, talk to your doctor.

It’s also important to talk to coaches and ask them if leagues or schools require annual physical exams for athletes. A physical examination by a doctor can detect the use of performance enhancing drugs in athletes (doping test). Ask coaches if any of their athletes have experienced performance enhancing drugs.

Stats

As many as four 4 American children and teens are using performance enhancing drugs such as anabolic steroids.

Subscribe to my newsletter and share this article if you think it can help someone you know. Thank you.

-Steph

P.S. If you’re in Miami and you like Caribbean food, go to my cousin’s bistro to eat Haitian food, click here .

Trick To Have Really More Energy

energy

What’s up ? This is THE stephane ANDRE !!! I watched an Olivier Roland’s video  and I learned some good stuff.

Often, during the day, we have a loss of energy. There is a trick I learned at my first karate class when I was 6 years old- At each class our Sensei (teacher) taught us how to breathe. There are 2 types of breaths :

Breathing with the upper body

This is the breathing that most people do. We can recognize a person who breathes from the top of the body because the shoulders rise with each inhalation . This type of breathing is not good because it reduces your performance, your well-being and your energy.

Diaphragmatic (abdominal ) breathing

diaphragmatic breathing

It’s diaphragm breathing. For simplicity, it’s abdominal breathing. This type of deep breathing calm down immediately, improves your well-being, increases your performances and your energy.

Here are some scientific studies on the beneficial effects of diaphragmatic breathing because the list is long. Scientific study Aa , Bb , Cc , Dd , Ee . It’s this type of breathing that is taught for fighting sports, singing, meditation, yoga, public speaking, etc.

Try during these next days to identify what type of breathing you do. You can put a reminder on your smartphone because it’s a test to be done over several days. The principle is that every time you realize that you’re breathing from top, made deep breaths to do the diaphragmatic (abdominal) breathing. You’ll quickly notice that you feel much better after that with a better state of mind.

The idea is that you’re more used to breathing with the diaphragm to have more energy in the day.

Subscribe to my newsletter and share this article if you think it can help someone you know. Thank you.

-Steph

P.S. If you’re in Miami and you like Caribbean food, go to my cousin’s bistro to eat Haitian food, click here.

This Problem Is Blocking Your Success

problem

What’s up ? This is THE stephane ANDRE !!! I watched an Olivier Roland’s video and I learned some good stuff.

In the last Leonardo da Vinci’s biography written by Walter Isaacson (who is also the author of the Steve Jobs biography, 2011), we can see that he was an extremely curious man. This curiosity allowed him to explore several different areas, boost his creativity and make a huge contribution to art. But the downside is that he kept changing projects.

Because of this, Leonardo da Vinci left a mind-blowing number of unfinished works of art. There are several scientific fields where he could have advanced the humanity of 2 centuries, if he worked more and published his results.

Attitude

This show us that we all have different attitudes to things that interest us, to our projects. We can explore something because we want to know how it works or master it to improve our lifestyle.

Attitude is very important in life. For example when you do something you like, you don’t have the same attitude as for something you like moderately or not at all. The last project you did, did you give the best of yourself to the end or not ? The question is whether you’re aware of the mission you want to accomplish through the project.

Mission

mission

In a project, the mission, the goal is essential. There are many people around me who say they want to be successful. They say things like : «  Yes, I want to be successful, if I find success around the corner, I would not say no. It would be cool ». But that doesn’t happen like that. To succeed in a mission, it’s necessary to give the best of oneself. And it can take many years, so don’t be naive. With internet, there is a myth that makes everyone believe that in 2-3 years we can be a millionaire, that’s wrong.

When I created my blog, I had friends who also had their blog or YouTube channel, but they all stopped. We didn’t have the same mission and the same attitude when we started. You can see in the top left of my blog this sentence : « I’m building my legacy ». This is my mission.

It’s really good to be curious, but once you’ve found something that interests you, focus on it. Work on this passion in « Guerrilla » mode to develop it, because it will become your main source of income. When I say « Guerrilla », it means that you give the best of yourself. You want to know what skill you have to learn, you want to learn from the best players in the field, you do tests to innovate, etc.

With a definite mission, a « Guerrilla » attitude and patience, you’ll have the success you deserve in your project.

Subscribe to my newsletter and share this article if you think it can help someone you know. Thank you.

-Steph

P.S. If you’re in Miami and you like Caribbean food, go to my cousin’s bistro to eat Haitian food, click here.

Start A Smart Company

startup company data

What’s up !!! This is THE stephane ANDRE. I watch an Olivier Roland’s video  and I learned some good stuff.

To create a company, most people advise to leave school or job to be 100% focused on creating the company. I advise you to start your business part-time and continue your school or job. An excellent method for this is « Lean Startup » . The principle of Lean Startup is to put on the market as fast as possible your product/service at minimum viable.

2 different methods

method scientific

Classic

Let’s take a closer look at what most people do. A person has an idea to start a company, so this person does a market research to minimize the risks. Then this person will seek financing with bank loans after calculating the needs of the business. These business needs based on a 3-years business plan that is extremely theoretical and hypothetical. You should know that in 99% of cases, as soon as the company is open and prospects are in contact with the products/services, these business plans have no connection with the reality of the field.

The problem with this method is that this person works for 1 year to create a product/service and when it’s available, this person realize that everyone doesn’t care. When the product/service isn’t selling, the stress rises enormously and you have to find a way to pay back people who lend money to your company.

Lean startup

With the Lean Startup’s method, when a person has a product/service idea, the principle is to find the minimum basic function of that which would interest the audience and the prospects who would be willing to buy. Then you have to do a test as soon as possible on the market. There is something very important that Michael Masterson said : « Before your business make its first sale, it’s nothing more than a set of unproven ideas that you are spending money on ».

That is why it’s necessary to set up a field test in the most real conditions possible with the most minimal version of your product/service.

Here is an example with someone who wants to buy a parking lot to rent it :

  • With the classic method, this person bought a random parking lot hoping to have many prospects interested in renting it.

  • With the Lean Startup method, this person will find an interesting parking lot to buy. Then this person will post an ad in an ads posting site and on social media and will wait to see if there are peope interested in renting it. If people call this person to say : « I’m interested in having your parking lot, I’d like to rent it », in this case this person will buy the parking lot. If nobody is interested in the parking lot, this person will not buy it.

Test quicky

test field

There are several other methods like this to test. In my case, it’s my blog to build my brand and until today, I’m doing it part-time. Here is a 3-part article in the power of a blog ( here  ).

Create my blog allowed me to :

  1. To know if I could find and keep my rhythm to write articles

  2. To know if I could share interesting things to create an audience

  3. To know if I could possibly monitize this blog with this audience

Once you have the idea, you need to test it as soon as possible to see what is happening on the field to collect feedback from the first customers and to know if you have an interesting business model or not. This test is excellent for eliminating a lot of uncertainty.

The cool thing about the Lean Startup method is that you’ll really start investing a lot of time, money and energy when you have your first customers who will help you improve your product/service.

Let things be clear, Lean Startup isn’t a magic formula, it’s necessary to act and start the process again, until you have a product/service that interest people.

Subscribe to my newsletter and share this article if you think it can help someone you know.

-Steph

Chi-Square Test With More Than 2 Categories

tableau chi square test

I have just enrolled in a Data Science course on Udemy  and I learned good stuff.

In this article, we will do a Chi-square test with more than 2 categories. We will use the A/B test « Country » which has 3 categories which corresponds to 3 countries : German, Spain and France. Select « Gender Actual » tab, make a copy with a right-click and select « Duplicate ».

tableau chi square test

Name the tab « Gender Actual (2) » by « Country Actual ».

tableau chi square test

In « Dimensions », move the variable « Geography » over « Gender » in « Columns » to replace « Gender » with « Geography ».

tableau chi square test

tableau chi square test

Here’s how to do an A/B statistical test when there are 3 categories. We’ll start with the classic method and then I’ll show you another way to do Chi-square test with any number of categories.

Let’s start with the classical method. In this case, there are 3 categories so we can’t use the online tool of the previous article. In the previous article we used an online tool with only 2 categories « Sample1 » and « Sample2 ». That’s why we’re going to use another online tool, click here  .

tableau chi square test

In this online tool, we can enter the values without using the total values. That is, we enter only the number of observations in each category. We simply need to enter the values that are on our A/B test. And I’m going to show you how to turn our A/B test into a table. In this way, it will be easier to enter the values in the online tool without making any mistakes.

Go to the « Show me » tool at the top right.

tableau chi square test

Click on « text tables »

tableau chi square test

tableau chi square test

Click on « Swap Rows ans Columns » button.

tableau chi square test

tableau chi square test

Cool, now you have a table arranged in exactly the same way as the online tool.

In the online tool, we will select 2 rows and 3 columns.

tableau chi square test

As we have 3 categories and 2 possible results, we enter our values exactly as in the table we just created on Tableau.

tableau chi square test

Perfect, our table is ready. You can click on the « Calculate » button.

tableau chi square test

tableau chi square test

As you can see, we observe the same thing as the other online tool. There is our indicator « p » value which is less than 5%. Which means there is a meaning.

tableau chi square test

This statistical significance means that these results are valid for the total number of the bank’s clients and not just for the sample of 10 000 clients. We observe similar differences with A/B test « Country » whose results are based solely on the sample of 10 000 clients. We can conclude that in the total number of the bank’s clients, it’s the clients in Germany who are more likely to leave the bank. This is how we do things cleanly.

You saw, this online tool limited by 5 by 5 tables so you can’t use this tool when you have 6 categories or more. But fortunately it’s possible to do Chi-square test with any number of categories. It’s a special method and for you to understand that, I’ll give you a theoretical explanation.

Here we have 3 countries : German, Spain and France.

tableau chi square test

What we’re trying to compare is the clients number leaving the bank in each of these countries.

tableau chi square test

With our basic A/B test based on a sample of 10 000 clients, we obtained 16% for France, 32% for Germany and 17% for Spain. Now the question is : « Do we observe the same results on the total clients number of the bank ? », it means : « In general, does the country have a significant effect on the clients number leaving bank ? ». Germany has the largest number of clients leaving the bank so the idea is : « Why would we need to compare the 3 countries at the same time ? ».

tableau chi square test

If we do an A/B test statistical test with Germany and France and we get a significant difference in the clients number leaving the bank between these 2 countries, then that would mean that in general, the country has a significant effect on the clients number who bank. Indeed, if we find by comparing Germany and France that the Germans are more likely to leave the bank than the French, we can consider that Spain will not change anything. Germans will always be more likely to leave the bank than the French. Maybe there will be a different relationship between Germany and Spain but there will always be a statistically significant difference between France and Germany with a larger number of clients leaving the bank in Germany than France.

Here is a way to confirm that this logic is true. There is a test and the participants of this test are German, Spanish and French. Imagine that this test was done without looking at what is happening in Spain. Now you get the result and you ask yourself the question : « Would the results changed if you added Spain ? ». The answer is « no » because there is no interdependence between Germany, Spain and France. That is, the decision to leave the bank in France and Germany doesn’t depend on Spain. And therefore, it’s quite correct to separate the categories by putting 1 aside to compare the 2 others. And as now we have 2 categories, we can do a Chi-square test with the online tool that we used in the previous article.

So let’s go back to our worksheet and put a country aside to compare only 2 countries. Select « Country » tab.

tableau chi square test

What we observe is that the difference between Spain and France is very small, so it wouldn’t be interesting to do a Chi-square test between Spain and France. It’s more interesting to do a Chi-square test between Germany and France and to prove that there is a statistically significant difference between these 2 countries. This will be enough to conclude that the country has a statistically significant impact on the clients number who leave the bank.

Selects « Country Actual » tab.

tableau chi square test

We will use the online tool of the previous article, click here  .

We will make a copy of « Country Actual » to have a bar chart with absolute values. Select « Country Actual », right-click and select « Duplicate ».

tableau chi square test

In « Show Me », select « horizontal bars ».

tableau chi square test

tableau chi square test

Removes « SUM (Number of Records )» from « Columns » and removes « Exited » and « Geography » from « Rows ».

tableau chi square test

tableau chi square test

In « Dimensions », move « Geography » in « Columns ».

tableau chi square test

tableau chi square test

In « Measures », move « Number of Records » to « Rows ».

tableau chi square test

tableau chi square test

In « Measures », move « SUM(Number of Records) » in « Label ».

tableau chi square test

tableau chi square test

In « Dimensions », move « Exited » in « Label ».

tableau chi square test

tableau chi square test

In « Dimensions », move « Exited » in « Colors ».

tableau chi square test

tableau chi square test

We also need total absolute values, which means the total number of men and women. There is a very fast way to get that. Right-click on the vertical axis and select « Add Reference Line ».

tableau chi square test

Then in « Value », click on the drop-down on the right and select « Sum » to have the total sum of the observations.

tableau chi square test

And in « Scope », you select « Per Cell » option to specify that you want the total sums for each category, male and female.

tableau chi square test

Now, we have the total sum at the top of the bars. We will modify labels to have the absolute values. In « Label », we will change « Computation » to « Value » and click on the « OK » button.

tableau chi square test

tableau chi square test

tableau chi square test

Here’s how to enter the data :

For « Sample1 » in #success, you enter 810 because there are 810 people who left the bank. For « Sample1 » in #trials, you enter 5014 because there are 5014 people in total.

For « Sample2 » in #success, you enter 814 because there are 814 people who left the bank. For « Sample2 » in #trials, you enter 2509 because there are 2509 people in total.

tableau chi square test

Here is the verdict : « Sample2 is more successful ». « Sample2 » corresponds to German’s clients and #success is :« yes, the client left the bank ». This verdict means that of all the clients from German are more likely to leave the bank than clients from France. And look, there is something important, it’s « p<0.001 ». This means that the « p » is strictly less than 0.001. As you can see, « p » value is very small, which concludes that the tests are statistically significant.

Ooh, there’s another thing I wanted to show you with the tab « age » with the 2 bar charts in parallel.

tableau chi square test

As you can see, there are many categories (more than 5) because each category corresponds to a 5-year ago group with clients of the bank aged from 15 to 90 years old. This is a lot of comparison but it would be a good exercise for you to find what are the 2 categories to compare that shows that there is a significant statistic difference.

I give you a hint, compare slices from 50 to 54 years old or from 35 to 39 years olds. In fact, you should compare all peer categories where you observe difference on this basic A/B test. Do a basic A/B test with absolutes values. Then do a Chi-square test to check if the difference is statistically significant, I mean, if the result is valid for the total number of bank’s clients.

This is a way to statistically validate the insights we see onTableau. You see, it’s not very difficult and it’s effective. Here is a way to find insights on Tableau and validate them.

Subscribe to my newsletter and share this article if you think it can help someone you know. Thank you.

-Steph

Validate Data Mining In Tableau With A Chi-Square Test

validate validation

I have just enrolled in a Data Science course on Udemy  and I learned good stuff.

In this article we will start using statistics. Don’t worry we’ll do something simple, we’ll use the Chi-square test in a basic way. There is a special section to learn how to do statistics at an advanced level.

I’ll explain why we’re going to learn how to use the Chi-square test. The results we have with theses 2 bar charts are good. We see on theses 2 bar charts that age has a significant impact on the rate of client leaving the bank. We also see in which age groups the clients leaves the bank the most and which age groups the clients leave the bank the least. With that we have good insights.

In the A/B test « Gender », we can see that there is a correlation between the male and female sex and the choice to leave the bank. But as I said before, this A/B test is basic. The results of a basic A/B test visually shows us what is probably happenning in reality but we aren’t 100% sure of these results. To validate these results, we need do to use statistical tests like Chi-square test.

Doing a report based on basic A/B test is very risky and you can have completely false insights. I don’t advise you to do it (unless you want to leave your job). It’s for this reason that using Chi-square will help us to have strong insights.

Chi-square will allow us to know if our results are statistically significant. Our results are based on a sample of 10 000 clients and Chi-square test will tell us if these results are due to chance effects or if these results can represent all the client of the bank.

For example in our A/B test « Gender », we observed that in our sample of 10 000 clients, women are more likely to leave the bank compared to men.

tableau data mining science chi square test a/b test

Now, we aren’t sure if the results of this sample represent the behavior of all the bank’s clients.

To use basic Chi-square test, we use an online tool. Click here  .

tableau data mining science chi square test a/b test

On internet, there are plenty of websites to do a Chi-square test but we’ll use this one so that you can understand how it works. To do a Chi-square test, we need to use absolute values and in our A/B test we have percentage.

Let’s go back to Tableau. We’ll create a new tab with a version of A/B test with absolute values. In this way, we keep the A/B test with the percentages. Do a right-click on the « Gender » tab and select « Duplicate ».

tableau data mining science chi square test a/b test

Name the new tab « Gender Actual » to specify that it’s absolute values.

tableau data mining science chi square test a/b test

To have the absolute values, move « Number of Records » in « Measures » to the « Marks » area and put it over top of « SUM(Number of Records ».

tableau data mining science chi square test a/b test

tableau data mining science chi square test a/b test

Move « Number of Records » in « Measures » to « Rows » over « SUM(Number of Records ».

tableau data mining science chi square test a/b test

Cool, we have our absolute values.

tableau data mining science chi square test a/b test

We also need total absolute values, which means the total number of men and women. There is a very fast way to get that. Right-click on the vertical axis and select « Add Reference Line ».

tableau data mining science chi square test a/b test

Then in « Value », click on the drop-down on the right and select « Sum » to have the total sum of the observations.

tableau data mining science chi square test a/b test

And in « Scope », you select « Per Cell » option to specify that you want the total sums for each category, male and female.

tableau data mining science chi square test a/b test

Now, we have the total sum at the top of the bars. We will modify labels to have the absolute values. In « Label », we will change « Computation » to « Value » and click on the « OK » button.

tableau data mining science chi square test a/b test

tableau data mining science chi square test a/b test

Perfect, we have the total amount of observation at the top of each bar : 4543 women and 5457 men. We have what we need to use our online tool.

tableau data mining science chi square test a/b test

OK, I’ll explain how this tool works. « Sample1 » and « Sample2 » correspond to the independent variable « Gender ». You choose in which order you enter the data, « Sample1 » for men or the opposite. In our case, we use « Sample1 » for women and « Sample2 » for men.

« #success » corresponds to the result Y=1, which means in our case « yes, the client left the bank ».

« #trials » is the total number of observations, which means the total number of women in « Sample1 » and the total number of men « Sample2 ».

That’s how you enter the data :

  • For « Sample1 » in #success, you enter 1139 because there are 1139 women who left the bank. For « Sample1 » in #trials, you enter 4543 because there are 4543 women in total.

 

  • For « Sample2 » in #success, you enter 898 because there are 898 men who left the bank. For « Sample2 » in #trials, you enter 5457 because there are 5457 men in total.

tableau data mining science chi square test a/b test

Here is the verdict : « Sample1 is more successful ». « Sample1 » corresponds to women and #success is :« yes, the client left the bank ». This verdict means that of all the bank’s client, women are more likely to leave the bank than men. And look, there is something important, it’s « p<0.001 ». This means that the « p » is strictly less than 0.001.

tableau data mining science chi square test a/b test

« p » is the value that indicates whether an independent variable has a statistically significant effect on a dependent variable. In our case, the independent variable is « Gender » and the dependent variable is « Exited », which is : « yes, the client left the bank ». So « p » is strictly less than 0.001, which means that the independent variable « Gender » has a statistically significant effect on the dependent variable « Exited ». This shows us that out of the total number of bank’s clients, women are more likely to leave the bank than men.

This is how we use Chi-square test with this online tool. This is the same principle on all online tools that you can find on Google or DuckDuckGo . You can repeat these instructions that I gave you with other tools, you will get the same results.

It’s cool with the Chi-square we validated the A/B test and to specify that this A/B test is validated, we’ll color the tab in green.

Right-click on the tab, select « Color » and select « Green ».

tableau data mining science chi square test a/b test

tableau data mining science chi square test a/b test

Perfect, now we’ll validate another A/B test. Selects « HasCreditCard » tab.

tableau data mining science chi square test a/b test

We’re going to create an A/B test « HasCreditCard » only with absolute values. To save time, right-click on « Gender Actual » tab and select « Duplicate ».

tableau data mining science chi square test a/b test

We’ll remove the green color on the tab « Gender Actual (2) ». Right-click on the tab and select « Color » and « None ».

tableau data mining science chi square test a/b test

You rename the tab « HasCreditCard Actual ».

tableau data mining science chi square test a/b test

Move the variable « HasCrCard » over « Gender » in « Columns ».

tableau data mining science chi square test a/b test

tableau data mining science chi square test a/b test

Excellent, everything is ready to do a Chi-square test. We’ll remove « Exited » labels to better see the absolutes values. Make a click and drag out.

tableau data mining science chi square test a/b test

tableau data mining science chi square test a/b test

Perfect, let’s go back to our online tool. In this case, « Sample1 » is « no », which means client who don’t have credit card and « Sample2 » for « yes », which means clients who have a credit card.

That’s how you enter the data :

  • For « Sample1 » in #success, you enter 613 because there are 613 clients who left the bank. For « Sample1 » in #trials, you enter 2945 because there are 2945 clients who don’t have a credit card.
  • For « Sample2 » in #success, you enter 1424 because there are 1424 clients who left the bank. For « Sample2 » in #trials, you enter 7055 because there are 7055 clients who have a credit card.

tableau data mining science chi square test a/b test

Let’s look at the verdict, it’s « No significant difference ». « p » value is very high, it’s above 5%. This confirms that the independent variable « HasCrCard » has no statistically significant effect on the dependent variable « Exited ». That was the conclusion we had made when we had done the A/B test with percentages.

We had seen that there was 21% of « Exited » (clients who left the bank) in the category « no » and 20% in the category « yes ». With these results we concluded that most likely the variable « HasCrCard » had no impact on the rate of clients who left the bank. Chi-square test confirms our conclusion and we can put the tab « HasCrCard » in green to say that it’s OK.

Right-click on the tab « HasCreditCard » => « Color » => « Green ».

tableau data mining science chi square test a/b test

tableau data mining science chi square test a/b test

Excellent, now, you can do a statistical A/B test with 2 categories. Soon, we will do statistical A/B tests with more than 2 categories.

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-Steph