Question

Assume that x has a normal distribution with the specified mean and standard deviation. Find the indicated probability. (Round your answer to four decimal places.)

μ = 51; σ = 14

P(40 ≤ x ≤ 47) =  

Answer 1

Solution :

Given that ,

mean = = 51

standard deviation = = 14   

P(40 ≤ x ≤ 47 )

= P[( 40 - 51 / 14 ) (x - ) / ( 47 - 51 / 14 ) ]

= P( - 0.79   z - 0.29 )

= P(z - 0.29 ) - P(z - 0.79 )

Using z table

= 0.3859 - 0.2148

= 0.1711