In introductory statistics software, what does using the $\mathrm{stats}$ command with a $\mathrm{by}$ clause typically accomplish?

• A. It calculates summary statistics separately for each group defined by the $\mathrm{by}$ variable.
• B. It creates a scatterplot of two variables.
• C. It merges two datasets based on a common variable.
• D. It performs a hypothesis test comparing two means.

Answer: (A)

Verified step by step guidance

1. Understand that the 'stats' command in introductory statistics software is generally used to compute summary statistics such as mean, median, standard deviation, etc.
2. Recognize that the 'by' clause is used to specify a grouping variable, which means the data will be divided into subsets based on the unique values of this variable.
3. When combining 'stats' with a 'by' clause, the software calculates the summary statistics separately for each group defined by the 'by' variable rather than for the entire dataset as a whole.
4. This approach allows you to compare descriptive statistics across different groups, which is useful for understanding group-level differences or patterns.
5. Note that other options like creating scatterplots, merging datasets, or performing hypothesis tests are different commands or procedures and are not the typical function of 'stats' with a 'by' clause.