z0 z1 z128 z1645 z196 z233 PZ

z=0

z=1

z=1.28

z=1.645

z=1.96

z=2.33

P(Z<=0)=0.5

P(Z<=1)=0.84

P(Z<=1.28)=0.9

P(Z<=1.645)=0.95

P(Z<=1.96)=0.975

P(Z<=2.33)=0.99

Given above table, the probability P(Z <= - 1) is

Solution

Given above table, the probability P(Z <= - 1) is

Probability of left hand side is equal to the probability of left hand side aand total sum of probability is equal to 1.

from the above table,

P(Z<=1)=0.84

which implies P(Z<=-1)=0.84