Calculate expected value for A/B test results

Last updated: December 26, 2025

Quick Overview

Given the following scenario about user conversion, calculate the the p-value.

Mastercard

Statistics & Math

Data Scientist

Mastercard

December 26, 2025

Data Scientist

Take-home Project

Statistics & Math

Medium

1,691 solved

Given the following scenario about user conversion, calculate the the p-value.

Statistics questions at Mastercard test your ability to reason quantitatively and design rigorous experiments. This Take-home Project question evaluates your understanding of statistical inference and its application to business decisions.

What the Interviewer Expects

Set up the problem formally with proper notation
Apply the correct statistical test with clear justification
Interpret results with appropriate caveats and confidence levels
Discuss practical significance vs statistical significance
Identify potential confounders and how to address them

Key Topics to Cover

Confidence intervals and significance levels

Regression analysis

Multiple testing correction (Bonferroni, FDR)

Bayesian vs frequentist inference

How to Approach This

Define your hypotheses (H0 and H1) clearly before performing any test.
Calculate required sample size BEFORE running an experiment, using power analysis.
Remember the Central Limit Theorem: sample means become approximately normal with large n.
Watch for Simpson's paradox. Always segment data by key dimensions.
Distinguish between statistical significance and practical significance.

Possible Follow-up Questions

How would you design a follow-up experiment based on these results?
How would you explain this result to a non-technical audience?
What assumptions does this test make, and how would you validate them?
How would you handle multiple comparisons?

Sharpen Your Skills on Codemia

Practice similar problems with our interactive workspace, get AI feedback, and track your progress.

Browse Statistics Questions

Sample Answer

Problem Formulation

To calculate the p-value for the A/B test on user conversion rates, let us define the following notation:

$n_A$ : the number of users in group A (control group)
$n_B$ : the number of users in g...

Solution Approach

Calculate the sample proportions: Determine $p_A$ and $p_B$ using the given data.
Calculate the pooled proportion: $p_{pooled} = \frac{k_A + k_B}{n_A + n_B}$
**Calculate...

Submit Your Answer

Markdown supported

Mastercard Data Scientist Interview Guide

Interview process, tips, and preparation timeline