Question

Assume the random variable x is normally distributed with mean μ = 80 and standard deviation σ = 4. Find the indicated probability.
P(x < 72) = _____ (round to four decimal places as needed).

Answer 1

Answer:

0.2278

Step-by-step explanation:

z = (x-μ)/σ,

where x is the raw score

μ is the population mean

σ is the population standard deviation

z => 72 - 80/4

= -2

Probability value from Z-Table:

P(x ≤ 72) = P(x = 72) => P(x < 72)

0.02275

Approximately =>0.2278