"Statistical Methods in Online A/B Testing" is a comprehensive guide to statistics in online controlled experiments, a.k.a. A/B tests, that tackles the difficult matter of statistical inference in a way accessible to readers with little to no prior experience with it.
"Statistical Methods in Online A/B Testing" is comprehensive, innovative, and practical – and dives into the underlying equations without getting caught up in
Continuous Metrics
Let’s now consider the case of a continuous metric such as the average revenue per user.
We randomly show visitors one of two possible layouts of our website, and based on how much revenue each user generates in a month we want to determine if one of the two layouts is more efficient.
Let’s consider the following case. 1. nX = 17users saw the layou.
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Discrete Metrics
Let’s first consider a discrete metric such as the click-though rate.
We randomly show visitors one of two possible designs of an advertisement, and we keep track of how many of them click on it.
Let’s say that from we collected the following information. 1. nX = 15 visitors saw the advertisement A, and 7of them clicked on it. 2. nY = 19 visitors s.
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Fisher’s Exact Test
Using the 2x2 contingency table shown above we can use Fisher’s exact testto compute an exact p-value and test our hypothesis.
To understand how this test works, let us start by noticing that if we fix the margins of the tables (i.e. the four sums of each row and column), then only few different outcomes are possible.
Now, the key observation is th.
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Pearson’s Chi-Squared Test
Fisher’s exact test has the important advantage of computing exact p-values.
But if we have a large sample size, it may be computationally inefficient.
In this case, we can use Pearson’s chi-squared testto compute an approximate p-value.
Let us call Oij the observed value of the contingency table at row i and column j.
Under the null hypothesis of .
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Statistical Significance
With the data we collected from the activity of users of our website, we can compare the efficacy of the two designs A and B.
Simply comparing mean values wouldn’t be very meaningful, as we would fail to assess the statistical significanceof our observations.
It is indeed fundamental to determine how likely it is that the observed discrepancy betwe.
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Student’S t-test
In most cases, the variances of the sampling distributions are unknown, so that we need to estimate them.
Student’s t-testcan then be applied under the following assumptions.
1) The observations are normally distributed (or the sample size is large).
2) The sampling distributions have “similar” variances σX ≈ σY.
Under the above assumptions, Studen.
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Welch’s t-test
In most cases Student’s t test can be effectively applied with good results.
However, it may rarely happen that its second assumption (similar variance of the sampling distributions) is violated.
In that case, we cannot compute a pooled variance and rather than Student’s t test we should use Welch’s t-test.
This test operates under the same assumpt.
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What Is A/B Testing?
A/B testingis one of the most popular controlled experiments used to optimize web marketing strategies.
It allows decision makers to choose the best design for a website by looking at the analytics results obtained with two possible alternatives A and B.
In this article we’ll see how different statistical methods can be used to make A/B testing suc.
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What is AB testing software?
AB testing software has the following primary functions.
The first job of AB testing tools is to show different webpages to certain visitors.
The person that designed your test will determine what gets showed.
An AB test will have a “control”, or the current page, and at least one “treatment”, or the page with some change.
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What is an AB test in statistics?
An AB test is an example of statistical hypothesis testing, a process whereby a hypothesis is made about the relationship between two data sets and those data sets are then compared against each other to determine if there is a statistically significant relationship or not.
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Where can I find a PDF version of abtestingstats?
Further information and a link for a more detailed preview (PDF download) can be found on the book website at www.abtestingstats.com.
You can also directly download a pdf preview of “Statistical Methods in Online A/B Testing” for the full table of contents and some of the introductory pages.
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Where can I find statistical methods in online a/B testing?
The long wait is finally over! “Statistical Methods in Online A/B Testing” can now be found as a paperback and an e-book on your preferred Amazon store.
The book is a comprehensive guide to statistics in online controlled experiments, a.k.a.
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Z-Test
The Z-testcan be applied under the following assumptions.
1) The observations are normally distributed (or the sample size is large).
2) The sampling distributions have known variance σX and σY.
Under the above assumptions, the Z-test exploits the fact that the following Z statistichas a standard normal distribution.
Unfortunately in most real appl.
