Answer:
0.9251
Step-by-step explanation:
z = (x-μ)/σ/√n where
x is the raw score
μ is the population mean
σ is the population standard deviation.
n is the random number of samples
(x-μ) = 0.83 months
σ = 7
n = 147
z = 0.83/7/√147
z = 0.83/0.5773502692
z = 1.43760217026
z ≈ 1.44
Determining the probability of the z score from the z table.
P(x<Z) = 0.92507
Approximately to 4 decimal places = 0.9251