Answer:
Step-by-step explanation:
Let X be average interest paid monthly by a bank's Visa cardholders
Given that X is N(28, 8)
In the following to find out probability we convert X to z score and use std normal distribution table
Z =
Probability being less than 1 is here equal to the proportion also.
A) P(X>32) = P(Z>0.5)=0.5-0.1915=0.3085
B) P(X>40) = P(Z>1)=0.5-0.3413=0.1687
C) P(X<19) = P(Z<-1.125)=0.5-0.0438=0.4562
D) We have to find 19th percentile here
Z =-0.88