Question 1203417
population mean is 320 employees with population standard deviation of 75.
population size is 20 industrial units.
sample size is 5 of these 20 industrial units.
sample mean is 300
z-score is indicated since standard deviation is taken from population.


standard error = standard deviation of population divided by square root of sample size = 75 / sqrt(50) = 33.54102.


z = (x-m)/s = (300-320)/33.54102 = -.59628


z is the z-score
x is the sample mean
m is the population mean
s is the standard error


critical z-score for two tailed confidence interval of 95% is z = plus or minus 1.95996.
test z-score of -.59628 is within these limits, indicating that the sample mean is consistent with the population mean.