Standard normal proportion. Use table B to find the proportion of a standard normal distribution that is: (a) below -1.42 (b) above 1.42 (c) below 1.25 (d) between 1.42 and 1.25

Answer :

A) The probability that z is below −1.42 : $P(z < −1.42) = 0.0778$

B) The probability that z is above 1.42 : $P(z > 1.42) = 0.0778$

C) The probability that z is below 1.25 : $P(z < 1.25) = 0.8944$

D) The probability that z is between 1.42 and 1.25 :

$P(1.25 < z < 1.42) =P(z < 1.42)−P(z < 1.25) =0.9222−0.8944 =0.0278$