Question

Given a normal distribution, X, with mean, 110, and standard deviation, sigma = 46.

A. What is the X value with Z-score equal to z = 0.65?   

B. What is the probability of X is less than or equal to 146.9? %

Answer 1

solution:

Given that,

mean = = 110

standard deviation = = 46

Using standard normal table,

Using z-score formula  

x= z * +

x= 0.65*46+110

x= 139.9

b.

P(X<146.9 ) = P[(X- ) / < (146.9- 110) /46 ]

= P(z <0.03 )

Using z table

= 0.5120