Answer:
a) when x = Raw Score: 42
Standard deviation = σ = -10.3
b) Raw Score: 81
Standard deviation = σ = 2.67
Explanation:
Find the standard deviation if the mean of a sample is 72, a z-score of 3
Z score formula is given :
z = (x-μ)/σ,
where
x is the raw score
μ is the population mean = 73
σ is the population standard deviation
z = 3
a) when x = Raw Score: 42
z = (x-μ)/σ
3 = 42 - 73/σ
Cross Multiply
3σ = 42 - 73
3σ = -31
σ = -31/3
σ = -10.3
b) Raw Score: 81
z = (x-μ)/σ
3 = 81 - 73/σ
Cross Multiply
3σ = 81 - 73
3σ = 8
σ = 8/3
σ = 2.67