Question

IQ test scores have a normal distribution with a mean of 100 and a standard deviation of 15 approximately what proportion of people have an IQ between 85 and 115

Answer 1

85 and 115 are 1 standard deviation above and below the mean (100-15 = 85, 100+15 = 115)

according to the empirical rule, this gives us a percentage of about 68%

Answer 2

I turned it into a fraction and ended up with 17/25
The answers are
a) 1/2
B) 2/3
C) 3/4
D) 4/5
Im lost *-*