Question

HELP PLEASE!!!

Scores of an IQ test have a bell shaped distribution with a mean of 100 and a standard deviation of 20. use the empirical rule to determine the following.

a. What percentage of people has an IQ score between 40 and 160
b. what percentage of people has an IQ score less than 60 or greater than 140.
c. what percentage of people has an IQ score greater than 160

Answer 1

Tips:

in a, they are saying the people are within 3 standard deviations from the mean.

in b, they are more/less than 3 standard deviations from the mean.

in c, they are strictly more than 3 standard deviations from the mean.

Answer 2

how would i figure those out though?

Answer 3

http://en.wikipedia.org/wiki/68-95-99.7_rule

Answer 4

Sorry, my language got a bit mixed up there.

in b, they are saying:

The percentage of people that are more than 3 standard deviations to the left and right

in c, the percentage of people that are more than 3 standard deviations to the right.

This will make sense of you look at it visually

Answer 5

hmmm >.<