CompTIA Data+ (DA0-002)Data AnalysisHard
A data analyst is comparing the performance of two different website layouts (Layout A and Layout B) by conducting an A/B test. They randomly assign users to one of the layouts and measure the average time spent on the page. After collecting data, they want to determine if there is a statistically significant difference in average time spent between the two layouts. Which inferential statistical test should they use?
- AANOVA
- BChi-squared test
- CPaired t-test
- DIndependent samples t-test
Show answer & explanationAnswer & explanation
Correct answer: D. Independent samples t-test
The scenario involves comparing the means of two independent groups (users assigned to Layout A vs. users assigned to Layout B) on a continuous variable (average time spent). The independent samples t-test is specifically designed for this purpose.
Why the other options are wrong
- A. ANOVA is used to compare the means of three or more groups, not just two.
- B. The Chi-squared test is used for categorical data to determine associations, not for comparing means of continuous data.
- C. A paired t-test is used when the two samples are dependent or related (e.g., before-and-after measurements on the same subjects), which is not the case here as users are randomly assigned to *different* layouts.
Independent Samples t-test
A statistical test used to determine if there is a significant difference between the means of two independent groups.
- Compares means of two separate populations/groups.
- Dependent variable is continuous, independent variable is categorical (two levels).
- Assumes independence of observations and often normality and equal variances.
Memory trick: T-TEST: Are THESE TWO groups different?