+0  
 
0
66
1
avatar

The ages of members of a policy action group are normally distributed with a mean of 33 years and a standard deviation of 2 years.

There are 400 members in the group.

About how many members are expected to be between 29 years old and 37 years old?

 

A) 272

B) 290

C) 354

D) 380

 Apr 1, 2020
 #1
avatar+23699 
+1

29 y/o  is 2 standard deviation BELOW the mean of 33

37        is 2 standard deviations ABOVE the mean

 

so  look at standard bell curve (see below) :   2 standard dev above and below the mean covers 95 % of the graph

95%  x 400 = 380   

 

 Apr 1, 2020

28 Online Users

avatar
avatar
avatar
avatar