Create new columns containing average of other columns

Hi @JessicaP94,
Welcome to R and the RStudio community!

So that we can help you solve your problem, can you post some reproducible data? There's more information about how to do that here: FAQ: How to do a minimal reproducible example ( reprex ) for beginners

It's great that you've shown us a photo of your data, but it will be easier for people to help you if you include a code snippet that creates some fake data that we can put directly into R and play around with to see what's not working.