Question

A population has a mean of 125 and a standard deviation of 16. A sample of 64 observations will be taken. The probability that the sample mean will be between 122.4 and 126.1 is

Answer 1

Answer:

0.61204

Step-by-step explanation:

μ = 125 ; σ = 16 ; n = 64

Probability that mean will be between 122.4 and 126.1

Z = (x - μ) / σ/sqrt(n)

x = 122.4

Z = (122.4 - 125) ÷ 16/sqrt(64)

Z = - 2.6 ÷ 2 = - 1.3

P(Z < - 1.3) = 0.0968

x = 126.1

Z = (126.1 - 125) ÷ 16/sqrt(64)

Z = 1.1 ÷ 2 = 0.55

P(Z < 0.55) = 0.70884

P(Z < 0.55) - P(Z < - 1.3)

0.70884 - 0.0968

= 0.61204