Question

Suppose a population of scores x is normally distributed with μ = 30 and σ = 12. Use the standard normal distribution to find the probability indicated. (Round your answer to four decimal places.)

Pr(24 ≤ x ≤ 42)

Answer 1

Solution :

Given that ,

mean = = 30

standard deviation = = 12

= P[(24 - 30 / 12) (x - ) / (42 - 30 / 12) ]

= P(-0.5 z 1)

= P(z 1) - P(z -0.5)

= 0.8413 - 0.3085

= 0.5328