You can also install the Analysis ToolPak add-in, select the column, click Data -> Data Analysis -> Descriptive Statistics. Gives mean, median, mode, SD and a bunch of other things. https://support.microsoft.com/en-us/office/use-the-analysis-...

Has been in Excel since 2007.

Since 1997 at least (except it’s under Tools there).

The problem states that Mary has an Excel file. It does _not_ state that Mary has an Excel software licence, or even a computer with which to run it.

You have LibreOffice nowadays.

The problem states that Mary has an Excel file. It does _not_ state that Mary has an access to a personal computer or a device allowing remotely accessing one.

My bad. The problem also does not state that Mary has adequate eyesight to use a computer or that she even has access to electricity to power a computer. Life is so hard