Final answer:
The 'description' section of the r help file for the sd() function provides the purpose and usage of the function.
Step-by-step explanation:
The 'description' section of the r help file for the sd() function provides the purpose and usage of the function. Here are two example sentences that could be included:
- The sd() function calculates the standard deviation of a given set of numbers.
- It is used to measure the spread or variability of data.