Hello Christina McCoy and welcome to the canvas community. Here are a couple troubleshooting ideas you can try:
Let us know if this helps. Thanks!
Just to add to what Priscilla already posted, just from reading through the documentation and playing with the app myself for a bit,I can only find the percentage of students who have answered one way or another but not the total number who have responded - wish I had a better answer to give!
In case anyone else finds this post in the future, as of January 2021, the Canvas Polls app is no longer supported or available to users.