Scores on a college entrance examination are normally distributed with a mean of 500 and a standard deviation of 100. What percent of people who write this exam obtain scores between 425 and 575?

a. 27.34%

b. 45.32%

c. 54.68%

d. 77.34%

Guest Jan 15, 2019

#1**+2 **

Are y'all working with z-scores? I'll have to look up my z-score table and get back in a few mins.....

well never mind the z-scores as this is a multiple choice....

ONE standard deviation above 500 and below 500 would be 400 and 600

from a standard bell curve, this represents 68%

question asks for 425 and 575 which would be slightly LESS than 68%

so answer C 54.68%

I will check z-scores to be sure....

OK....checked z-score tables and find 54.68%

ElectricPavlov Jan 15, 2019