Standard Deviation

Question

Suppose that the scores on particular FDMAT 108 unit exam at a University were normally distributed with a mean of 78 and a standard deviation of 10.

1. About what percentage of the scores were above 68 for this unit exam?
%
(Round to the nearest whole number.)

2. If 1,700 students took the exam, approximately how many scored above 88?

(Round to the nearest whole number.)

3. What is the standard score for a unit exam score of 82?

(Round to two decimal places.)

Answer 1

1. 17%

mean of 78, so that means 50% are above 78, we are one standard deviation away which is 67%/2=33.5 ( 1 standard deviation on 1 side.)

100-50-33

2. 289

mean is 78 , 88 is 1 standard deviation above 88. so that is about 17% 1700*.17=289, 50% is 78 and below and , 67%/2=33.5 ( 1 standard deviation on 1 side.)