Question

The ages of students in a school are normally distributed with a mean of 15 years and a standard deviation of 2 years. Approximately what percent of the students are between 14 and 18 years old?

24.17%
62.47%
30.85%
93.32%

Answer 1

@CBARREDO1

Answer 2

Well,
we have :
mean = 15 years
SD = 2 years
let be F the distribution of the N(0,1) is the z-table,
then
P( 14 < Age < 18) = P( - 0.5 < (Age - mean)/SD < 1.5)
= F(1.5) - F( -0.5)
= .93319 - .30854

-----------------------> P( 14 < Age < 18) = .62465 second answer

Answer 3

B. 62.47

Answer 4

Wait wait wait, Can someone tell me exactly how to do this as i have 2 more questions like this one and i should probably figure out how to do them properly

Answer 5

Pizza delivery times at Pizza Time are normally distributed with a mean time of 27 minutes and a standard deviation of 3 minutes. Approximately what percent of pizzas are delivered between 24 and 30 minutes?

32%
68%
95%
99.7%

Answer 6

this is the next one i have to do.