For a normal distribution with mean of 75 and standard deviation of 25, the proportion of the scores between 90 and 100 is
A) .0670
B) .1000
C) .1156
D) .1587
E) .2257
F) .4000
G) .4330
H) .5670

Question

Quizplus · Accepted Answer

To find the proportion of scores between 90 and 100 in a normal distribution with a mean of 75 and a standard deviation of 25, we use the Z-score formula: Z = (X - μ) / σ, where X is the score, μ is the mean, and σ is the standard deviation. For X=90, Z = (90-75)/25 = 0.6. For X=100, Z = (100-75)/25 = 1. The area between Z=0.6 and Z=1 in the standard normal distribution table corresponds to approximately 0.1156, which is the proportion of scores between 90 and 100.

For a Normal Distribution with Mean of 75 and Standard