Answer:
(a) 68% of people has an IQ score between 87 and 113.
(b) 5% of people has an IQ score less than 74 or greater than 126.
(c) 0.15% of people has an IQ score greater than 139.
Step-by-step explanation:
Given information:Scores of an IQ test have a bell-shaped distribution,
mean = 100
standard deviation = 13
According to the empirical rule
68% data lies between and
.
95% data lies between and
.
99.7% data lies between and
.
(a)
Using empirical rule we can say that 68% of people has an IQ score between 87 and 113.
(b)
Using empirical rule we can say that 95% of people has an IQ score between 74 and 126.
The percentage of people has an IQ score less than 74 or greater than 126 is
P = 1- percent of people has an IQ score between 74 and 126.
P = 1- 95%
P = 5%
Therefore 5% of people has an IQ score less than 74 or greater than 126.
(c)
Using empirical rule we can say that 99.7% of people has an IQ score between 61 and 139.
The percentage of people has an IQ score less than 61 or greater than 139 is
P = 1- percent of people has an IQ score between 61 and 139.
P = 1- 99.7%
P = 0.3%
The percentage of people has an IQ score greater than 139 is
Therefore 0.15% of people has an IQ score greater than 139.