In a normal distribution, the formula for calculating z score is expressed as
z = (x - μ)/σ
where
σ is the population standard deviation
x is the sample mean
μ is the population mean
From the information given,
x = 70
μ = 170
σ = 40
By substituting these values into the formula,
z = (70 - 170)/40
z = - 2.5
The z score is - 2.5
