Question

I have a test to do today and I need help with it, i don't understand any of it. I will copy and paste it here: IQ scores are normally distributed with a mean of 100 and standard deviation of 15. 1) About what percent of people would have IQ between 85 and 115? 2) About what percent of people would have IQ between 70 and 130? 3) About what percent of people would have IQ above 130? 4) If a school had 255 students, about how many would you expect to have an IQ less than 70? 5) If a school had 1531 students, about how many would you expect to have an IQ greater than 145? 6) If a school has 354 students with an IQ between 100 and 130, about how many students does the whole school have?

Answer 1

68%

Explanation:

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. About 68% of individuals have IQ scores in the interval 100 ± 1 ( 15 ) = [ 85 , 115 ] .