For given sample of salaries of four employees, the variance of their salaries is: 26 thousands of dollars
The formula for the variance is,

where,
 = sample variance
 = sample variance
 = the value of the one observation
 = the value of the one observation
 = the mean value of all observations
 = the mean value of all observations
n = the number of observations
For given question,
n = 4
First we find the mean of their salaries.
(33 + 31 + 24 + 36 ) / 4 = 31
So, 
Using the formula for variance ,

Therefore, for given sample of salaries of four employees, the variance of their salaries is: 26 thousands of dollars 
Learn more about the variance here:
brainly.com/question/13673183
#SPJ4