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A/B Test for Pricing Page

EasyStatistics & Probability00:00
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Problem

Business Context

StreamCart, a SaaS company, tested a redesigned pricing page intended to increase free-trial signups. The product manager wants a statistically sound recommendation on whether to launch the new page.

Problem Statement

You are given results from a 21-day randomized A/B test. Determine whether the new pricing page produced a statistically significant improvement in signup conversion rate versus the current page.

Given Data

GroupSample SizeSignupsConversion Rate
Control (current page)18,4002,20812.0%
Treatment (new page)17,9002,32713.0%

Additional test settings:

ParameterValue
Significance level0.05
Test typeTwo-tailed

Requirements

  1. State the null and alternative hypotheses.
  2. Compute the sample conversion rates for both groups.
  3. Calculate the pooled proportion and pooled standard error for a two-proportion z-test.
  4. Compute the z-statistic and two-tailed p-value.
  5. Construct a 95% confidence interval for the difference in conversion rates.
  6. Decide whether the result is statistically significant at the 5% level.
  7. Explain whether the observed lift is large enough to matter from a business perspective.

Assumptions

  • Users were randomly assigned to control and treatment.
  • Each observation represents a unique user.
  • Independence between users is reasonable.
  • Normal approximation is appropriate because both groups have large sample sizes and sufficient numbers of successes and failures.