Compute the standard deviation of the following set of data to the nearest whole number: 8, 12, 15, 17, 18 a) 3 b) 4 c) 13 d) 14

We have that

set of data [8, 12, 15, 17, 18]

step 1
Find the mean
[8+ 12 + 15 + 17 + 18]/5> 70/5> 14

step 2
 for each number: subtract the Mean and square the result
(8-14)²>36
(12-14)²> 4
(15-14)²> 1
(17-14)²> 9
(18-14)²> 16

step 3
 work out the mean of those squared differences
[36+4+1+9+16]/5> 66/5> 13.2> this value is called the "Variance"

step 4
Take the square root of that
standard desviation=√13.2> 3.63> 4

the answer is
4