Question

X has a normal distribution with the given mean and a standard deviation. Find the indicated probability. (Round your answer to four decimal places.) μ = 108, σ = 15, find P(111 ≤ X ≤ 129)

Answer 1

Solution :

Given that,

mean = = 108

standard deviation = = 15

P (111 x 129 )

P ( 111 - 108 / 15 ) ( x -  / ) (129 - 108 / 15 )

P ( 3 / 15 z 21 / 15 )

P ( 0.2   z 1.4 )

P ( z 1.4 ) - P ( z 0.2 )

Using z table

= 0.9192 - 0.5793

= 0.3399

Probability = 0.3399