+0  
 
0
64
1
avatar+493 

Scores on a standardized test are normally distributed with a mean of 550 and a standard deviation of 45.

Approximately what percent of students scored between 560 and 580?


16%


25%


33%


49%

 Feb 17, 2020
 #1
avatar+109450 
+1

[ 560 -550] / 45 = .222   

 

Using a table of z scores....the  % associated with  a z  score  of  .22  ≈ 58.7%

 

[ 580 - 550 ] / 45 =   30 / 45  =  .66

 

Again....using a z score table the %  associated with a  z  score of  .66  ≈ 74.5%

 

So.....the %  scoring  between        560 and 580  ≈ [ 74.5 - 58.7 ] ≈  15.8%  ≈  16%

 

 

 

cool cool cool

 Feb 17, 2020

13 Online Users

avatar