Question

. Assume that a set of test scores is normally distributed with a mean of 100 and a standard deviation of 20. Use the 68-95-99.7 rule to find the following quantities:
(Hint: Make a drawing and label first)
a. Percentage of scores less than 100
b. Relative frequency of scores less than 120
c. Percentage of scores less than 140
d. Percentage of scores less than 80
e. Relative frequency of scores less than 60
f. Percentage of scores greater than 120

Answer 1

a. In a normal distribution, the mean, median and mode have the same value. Does that help?

b. 120 = mean% + 34% (1/2 of 68%)

Use similar processes to solve the remainder of your questions.

Answer 2

if you have a body temperature of 99.00„aF, what is your percentile score?