What does the CountIF function do in Excel?

The CountIF function in Excel is designed specifically to count the number of cells within a specified range that meet a certain condition or criterion. This function is particularly useful when you need to assess data based on specific characteristics, such as counting how many times a particular value appears within a dataset or how many entries match a specific condition, such as being greater than a certain number or equal to a specific text string.

By using the CountIF function, you can perform targeted counts that help in data analysis and reporting, allowing you to focus on certain subsets of your data instead of counting all entries indiscriminately. For example, you can use it to find out how many times the word "Completed" appears in a column of statuses, providing insights into project completion rates.

In contrast, other choices imply broader or different counting mechanisms. Counting all values in a range doesn't filter or limit the count based on any criteria, counting cells with text only restricts the count to text entries and ignores numbers or blank cells, and counting unique values identifies distinct entries rather than those meeting a specific condition. Thus, the CountIF function's specialized capability to count based on criteria is what makes it the correct choice here.