+511 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%
+129852 [ 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%
