For a sample of n = 30 scores, a score that is 6 points above the mean has a z-score of z = 1.50. What is the sample standard deviation?

Question

Please provide how to solve :)

Answer 1

If the single score is 6 above the mean, then the standard deviation can be found using the following equation. The sample size of 30 just determines that this value can use a normal distribution

X = µ + Z•σ

X-µ = 6 = Z•σ

1.5σ = 6

σ = 6/1.5 = 4

Thus the standard deviation is 4.