AWS Certified Machine Learning – SpecialtyExploratory Data AnalysisMedium
A retail company is analyzing sales data from their e-commerce platform. They want to determine if there is a statistically significant difference in average daily sales between two distinct marketing campaigns (Campaign A vs. Campaign B). The sales data for both campaigns are normally distributed, and the variances are assumed to be equal. Which statistical test should they use?
- APaired samples t-test
- BIndependent samples t-test
- CChi-squared test
- DANOVA
Show answer & explanationAnswer & explanation
Correct answer: B. Independent samples t-test
An independent samples t-test is used to compare the means of two independent groups (Campaign A and Campaign B) on a continuous variable (average daily sales). The problem states that the data is normally distributed and variances are equal, which are key assumptions for this test.
Why the other options are wrong
- A. A paired samples t-test is used when the two groups are dependent or related (e.g., before-and-after measurements on the same subjects), which is not the case here.
- C. A Chi-squared test is used for categorical variables to test for association or independence, not for comparing means of continuous variables.
- D. ANOVA is used to compare the means of three or more groups, not just two.
Independent Samples T-test
A statistical hypothesis test used to determine if there is a significant difference between the means of two independent groups on a continuous outcome variable.
- Compares means of two distinct groups.
- Assumes independence of observations.
- Requires continuous data, approximate normality, and often equal variances (or use Welch's t-test).
Memory trick: T-test: 'Two' groups, 'T'esting means.