DA0-002 Data Analysis Practice Question
A company wants to determine if there is a significant difference in the average sales revenue between two different store layouts. They collect sales data from 30 stores with Layout A and 30 stores with Layout B. Which statistical test is most appropriate for comparing the means of these two independent groups?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Two-sample t-test
The two-sample t-test (independent t-test) compares the means of two independent groups. A paired t-test would be for dependent samples, ANOVA for three or more groups, and chi-square for categorical variables.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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ANOVA
Why it's wrong here
ANOVA is designed to compare means across three or more groups, not two. The scenario involves exactly two independent groups (Layout A and Layout B), so a two-sample t-test is required to assess the difference in means. ANOVA would be tempting if the question involved comparing sales revenue across three or more store layouts, where it would correctly test for any overall difference among group means.
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Chi-square test
Why it's wrong here
Chi-square test is for categorical variables, not continuous means.
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Paired t-test
Why it's wrong here
A paired t-test requires dependent samples, where each data point in one group is directly linked to a specific data point in the other group (e.g., before-and-after measurements on the same stores). Here, the 30 Layout A stores and 30 Layout B stores are entirely separate, independent groups, so the paired t-test’s assumption of dependency is violated. It is tempting because both tests compare two means, and a paired t-test is the correct choice when the same subjects are measured twice or matched pairs are used.
- ✓
Two-sample t-test
Why this is correct
Correct for comparing means of two independent groups.
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