See the FAQ: How to do a minimal reproducible example reprex for beginners.
Do you see something like this when you perform str(sleep_analysis)?
str(warpbreaks)
#> 'data.frame': 54 obs. of 3 variables:
#> $ breaks : num 26 30 54 25 70 52 51 26 67 18 ...
#> $ wool : Factor w/ 2 levels "A","B": 1 1 1 1 1 1 1 1 1 1 ...
#> $ tension: Factor w/ 3 levels "L","M","H": 1 1 1 1 1 1 1 1 1 2 ...