Question

X has a normal distribution with the given mean and standard deviation. Find the indicated probability. (Round your answer to four decimal places.)

μ = 39, σ = 20, find

P(32 ≤ X ≤ 49)

Answer 1

Solution :

Given that ,

mean = = 39

standard deviation = = 20

P( 32 x 49 )

= P[(32 - 39 / 20) (x - ) / (49 - 39 / 20) ]

= P( -0.35 z 0.5 )

= P(z 0.5 ) - P(z -0.35 )

Using z table,  

= 0.6915 - 0.3632

= 0.3283

P( 32 x 49 ) = 0.3283

Probability = 0.3283