1.13 Sum or Average values across multiple variables

The Center for Epidemiological Studies Depression Scale (CESD) is series of questions asked to a person to measure their level of depression. CESD is calculated as the sum of all 20 component variables, and is already on this data set. Let’s create a new variable named sleep as subscale for sleep quality by adding up question numbers 5, 11, and 19.

Reference: http://cesd-r.com/cesdr/

depress$sleep <- depress$c5 + depress$c11 + depress$c19
## # depress <- depress %>% mutate(sleep = c5+c11+c19) # Not run. dplyr example
## # depress <- depress %>% mutate(across(c(c5, c11, c19), mean)) # Not run, across() example

summary(depress$sleep)
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##   0.000   0.000   1.000   1.167   2.000   7.000