Selected Answer
Hello Susan,
I don't know of a way to allow data on a protected sheet to be sorted but it is possible to allow filtering. To allow filtering do the following before protecting the sheet. Select the table of data including headings and then on the Data tab click on "Filter". The sheet can now be protected. Cells in the table can be locked to prevent corruption of the data. Your users can now filter the data (using the down arrows in the header row) to only include the data they are interested in.
Update 10:53pm
Just found this link which describes how to allow sorting and filtering of a protected sheet.
Allow Sorting and Filtering
If this solves things for you please remember to mark my answer as Selected.
Cheers :-)