Using the z score formula when a random number of samples is given =
z = (x-μ)/σ/√n, where
x is the raw score
μ is the population mean
σ is the population standard deviation = 7
n is random number of samples = 83
Note that:2.2 dollars = x-μ
z = 2.2/7/√8.3
z = 3.51402
Probability value from Z-Table:
P(x<27.7) = 0.99978
P(x>27.7) = 1 - P(x<27.7) = 0.00022069
Approximately = 0.000221
Hence, the probability that the sample mean would differ from the true mean by greater than 2.2 dollars if a sample of 83 5-gallon pails is randomly selected is 0.000221
