What does the COUNT function do?

The COUNT function is designed to count the number of non-missing values in specified variables within a dataset. This is particularly useful in data analysis where understanding the quantity of valid entries is crucial. For example, if you have a dataset with several observations where some values are missing, using the COUNT function allows you to get an accurate representation of how many entries contain data, thus aiding in ensuring the integrity of subsequent analyses.

On the other hand, the other options relate to different functionalities: counting all observations in a dataset pertains to measuring the total number of entries regardless of their completeness; tallying unique values focuses on determining how many distinct entries exist within a variable; and providing a frequency distribution involves summarizing the occurrence of each unique value in a dataset rather than merely counting the non-missing entries. Therefore, the specific function of counting non-missing values aligns accurately with the purpose of the COUNT function.