In calculating for the variance, we use the actual sample size and not the population size. In this case since we are only using a sample size of 51 employees, then s^2 or sample variance refers to the variance of 51 employees.
Therefore the answer is letter D. 51
Variance measures how variate in the data set is spread from mean and from other variates in data set.
Variance(s²), is calculated by difference between each number in the data set and the mean,and then squaring the result, and then dividing the sum of the squares of each variate in the new data set by total number of variate in new data set.
Now coming to the Question
Total Population=606
Sample Size chosen for employee salary=51
Since, sample size
[tex]=\frac{51}{606}\times 100\\\\=\frac{5100}{606}\\\\=8.42[/tex]Percent
Sample size is too small that is only , 8.42 % of total data set.
So, it would refer to variance of only 51, employees salaries.
Option D--51
