Quantitative 2

Help me In solving question 24
I got the mean correct 14.67
But unable to solve for Sample standard deviation

Answer is C. I could do it manually or I could put my calci to work. TI BA II Plus Pro.

you just have to remember the formula

sample variance = (sum of { (x - mean of x)^2 } ) / (n - 1)
here, x take the values of -.67, 1.71 and 42.96.
because you have 3 data points, n = 3

once you find the sample variance, all you have to do is take the square root to get the sample standard deviation.