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Questions tagged [ab-test]

A/B testing, also known as split or bucket testing, is a controlled comparison of the effectiveness of variants of a website, email, or other commercial product.

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A/B testing ratio of sums

Context Consider the following scenario for a company selling goods online. A user can purchase several items (i.e. basket of items), some of which are of particular importance and are tracked ...
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How to calculate significance for an A/B test for average revenue per daily active user over a 1-week test period?

One simple approach is to use "per active day" metrics. e.g. "revenue_per_active_day" . However there is a fundamental flaw with this approach. e.g. during a 7-day period, let's say user 1 is active ...
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AB Testing vs Hypothesis Testing

I'm having trouble making the full connection between AB Testing and Hypothesis testing. Hypothesis Testing Conducting a test to compare two means, we need the standard deviation of both samples, and ...
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A/B testing formula: How to calculate the necessary sample size to run an A/B test?

I heard there is a formula to estimate the sample size when running an A/B test, using the following: . significance level . power . expected standard deviation of the change in the metric we are ...
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statistical significance of A B test if some observation are removed due to errors

I have ran an A/B test and using chi-square test of independence, results shows that group A improves on group B by less than 5% (statistically significant) YAY!!! Unfortunately, after few checks I ...
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1answer
73 views

AB test sample size calculation by hand

Evan Miller has created a well-known online AB test sample size calculator. For the sake of being able to program and modify this formula, I would like to know how to calculate sample size Evan Miller-...
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1answer
16 views

A\B Testing with Sorting

In my company while splitting site users for AB test we do the following: we choose parameters that seem the most important for us (for example: gender, life time value, average check, etc), if they ...
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1answer
22 views

how to present results for two group success rate with confidence interval

I have two groups A and B, and for each data point I have two possible outcomes, success and failures. For each group, I have calculated the success rate, and the confidence interval for a binomial ...
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Statistics of Diff in diff with optimal group

I am trying to run a diff in diff to measure the impact of a feature. I want to run the experiment per geo region and I have 90 regions. To run a proper diff in diff I should split in have the ...
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11 views

Conversion/Revenue Attribution in AB experiments

I have a question on A/B testing attribution. I have a test running on mobile app and website at the same time. Unfortunately the way the test is designed ...
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1answer
20 views

In AB test do the sample size calculations represent the minimum or maximum size required for measuring difference between the test and control

A quick question on the frequentest approach of sample size calculation. I recently came across this below note: The sample size required should be strictly enforced; if the power analysis shows ...
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A/B test : Is there a way interpreting factor “A” group is greater than factor “B” group?

Plz.. understand my lack of English skills.. T.T I have a problem dealing with statistical hypothesis testing. To be specific, we have two special delivery method like (new) : method "A", (old) : ...
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Good numbers, but something feels wrong

This is more a qualitative question than a quantitive one. I have done an A B test to try to increase use of a particular feature (feature 1) by increasing discoverability. I measure it by seeing ...
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2answers
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Multi-armed bandit vs AB testing

I'm trying to understand the difference between AB Testing and Multi armed bandit and when we should use one of the other. It seems to me that Multi-armed bandit algorithms are statistically valid and ...
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Pairwise vs aggregate A/B/n hypothesis testing

I'm currently running a hypothesis test on multiple variants (say $n$ variants) of a webpage, trying to optimize conversion, and am unsure if I should run pairwise hypothesis tests of each variant ...
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3answers
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Eliminating variation in sample size for A/B tests

Firstly, I'll apologise for my limited understanding on this topic. Let's say I am running an A/B test with a pool of 20,000 prospects and I split them 50/50 into A and B. The problem is, the ...
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What statistical test is best to compare ratios within each groups

I am doing a a/b test. I am interested in finding difference in ratio of revenue after the campaign vs before for both the groups. Both groups are random split from same population subjected to two ...
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Possible questions on testing on hypothesis in A/B testing for a position of a data scientist (EDITED)

What are some possible machine learning and statistics questions on the subject of A/B testing for a position of a data scientist in Ad Tech industry working in retargeting? I'm interviewing for such ...
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1answer
17 views

MVT/ABn pricing test comparison

I have results for a a 5 variant pricing test: A 0% (control group) B +5% C -5% D +10% E -10% Below are my results (all normalised to give if exactly 20% of traffic goes through the variant, ...
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1answer
24 views

Which of these scenarios are multiple or repeated comparisons?

I believed I knew what multiple comparison or repeated testing meant but upon reading more on the subject and listening to others I have become more confused. My confusion started with A/B testing ...
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What would be a good sampler from pymc3 for highly skewed data

I have a gamma distributed data which is highly skewed - alpha=0.15, beta=0.001. I would like to perform mcmc to find the delta between two gamma distributions. I get the following error: I suspect ...
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1answer
32 views

P-value and confidence interval in MVT testing

Context: website A/B testing When calculating P-value and confidence intervals for each variation in an experiment with more than 2 variations (control, variation 1, variation 2 ...) should there be ...
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47 views

How to implement bayesian ab testing to gamma distributed data using pymc3

I found a simple implementation for Bernoulli distributed data of the bayesian ab tesing using pymc3 in the Probabilistic Programming and Bayesian Methods for Hackers book: http://nbviewer.jupyter.org/...
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AB testing for low traffic sites

I am working on a AB test on a specific page that has very low traffic (like ~1200 per day). As most of us know, features with smaller traffic need more time to detect any significant change unless ...
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Sampling A/B test results (revenue per visitor vectors)

I have two vectors of the control version A and test version B. These vectors contain revenues by visitor. So A version has 3020 visitors who didn't purchase and B respectively 2811. Revenue data ...
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35 views

Statistical analysis to find causality?

I have the following two groups of data: (a) jobs done before a certain feature was released in our software (b) jobs done after the feature was released in our software The purpose of the feature ...
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1answer
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Do I need to discard 90% of experiments so that the sample is independent?

I'm reading OpenIntro Statistics by David Diez and he says that for running an inference on a one sample mean we need to validate that the observations are independent: I'm running an A/B test and I ...
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24 views

How to measure metric baseline?

During planning of an online A/B test, after we choose a success metric, we need to estimate the sample size required to detect a minimum effect. Usually this formula[1] is used: $n = 16 \frac{σ^2}{δ^...
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Weighted and Paired-comparison tests

We have an application with 7 different update versions. The goal is to prove to the customers that updating to the newer version is beneficial for you, since you will face with less bugs. The ...
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0answers
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Non-inferiority experiment: results fluctuate daily, significant on some days and not others

I am trying to interpret the results of an experiment after the fact (was not involved in setting up, determining sample size, etc). The experiment had the aim of 'not breaking anything', so there was ...
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0answers
10 views

Check for difference for 2 groups with 4 possible test results

I need to calculate sample size for test with 2 groups of people where test results are 4 possible outcomes: 1 - no, 2 - possibly no, 3 - possibly yes, 4 - yes. What kind of statistics test can I use ...
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1answer
34 views

Non-inferiority margin and minimum detectable effect vs sample size

I am trying to understand why testing for non-inferiority requires pretty much the same sample size as testing for superiority (I assume the latter is the same as a one-sided test for a given MDE). I ...
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1answer
48 views

A/B testing parity (A=B)

I can't find any information on how to run an A/B test that shows that the new implementation B is likely at least as good as A. My metric is visitor conversion so I could use a test of proportions ...
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0answers
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Understanding interim analysis and alpha spending functions

I have to perform an A/B test with interim analysis and found some literature about methods designed to preserve the global Type I error rate by adjusting the $\alpha$ level for each peeking. ...
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23 views

Single Sample Hypothesis Z-test V.S. Two Populations, t-test with Hypothesis

for website A/B test, I split the traffic, 50% to control group, 50% to Test group. ...
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1answer
45 views

Confidence boundaries for an AB test [closed]

Given an AB-test, I have two variants running over a certain timeperiod gathering data. I split the time period up in smaller frames and cumulative add the population for the given variant as well as ...
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2answers
27 views

experiment with 3 arms: analyzing results when one of 3 pairwise tests shows significance

I have an experiment with 3 groups: group 1 got no email group 2 got an email with 10 dollars incentive group 3 got an email with 20 dollars incentive to convert to a specific product. Conversion ...
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1answer
48 views

How do I measure impact of an intervention of time series without historical data of the same series?

I'm trying to evaluate the impact of an intervention in the most statistically accurate way possible but I'm having a hard time figuring out a way measure incremental growth along with statistical ...
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Assessing A/B test results using Python

Problem's setting Assume having results of an A/B test. You let you users experience two variants of your website and you counted how many converted: ...
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1answer
213 views

Checking independence of A/B/C/… test results using Python

Assume I collected the following results from an A/B/C/D/E test: ...
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69 views

What is the practical difference between different significance calculators for A/B tests?

As background information I could say that we are currently studying A/B testing in University digital marketing class. As I have quite little background in statistics I am little bit wondering about ...
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1answer
485 views

Confidence Intervals for Mean Difference between Actuals and Forecast

I am trying to assess the influence of a product change compared to a hypothetical forecast. I use a time series model to predict a realistic future and compare it to the observed actuals. I am ...
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1answer
59 views

What role does standard deviation play in hypothesis testing?

I'm new to hypothesis testing in statistics. Say if we were to run an experimental trial on two control groups (split of 50% each), and after a large enough sample size, conclude by looking at just "...
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1answer
301 views

What is difference of Difference in Difference(DiD) and A/B Testing?

I am learning DiD and find it similar to A/B Testing. What's the difference between these two testing methods?
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2answers
1k views

What does statistically insignificant mean?

Say if an A/B test proves to be insignificant but the test group shows that its doing better than the control group, what would be some of the reasons that the test is insignificant?
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32 views

A/B testing on sparse metrics

Out of my entire population(in this case all the possible posts) only .05% of my posts will be liked. I introduce a new post format, and design an A/B test to test my old post format to see if my new ...
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1answer
100 views

Selecting Bayesian priors for the dependent data

I have goal of measuring CTRs of several titles of an article on a website using Bayesian approach. In a simple setup, what one will do is to select Beta Prior (for example Uniform distribution) and ...
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1answer
31 views

Contaminated AB testing

Suppose that you are a product manager who wants to run a test for a new product. You consult your statistician, select a sample of customers and run the test. Apparently, another product manager ...
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1answer
67 views

Are A/B testing problems intrinsically a multiple testing problem?

Can we convert any A/B testing problem into a multiple testing problem?