Question

can someone help me find the 8th percentile on a normal distribution with mean -6 and variance 64.

Answer 1

You basically want to find k where

P(X < k) = 0.08

So you can use a calculator or an inverse normal table

Answer 2

how would you go about using your calculator to solve this problem?

Answer 3

I'm assuming you have a TI 83 or TI 84?

Answer 4

yes

Answer 5

which one?

Answer 6

the 84

Answer 7

hit second, then hit the vars key

Answer 8

scroll to "invNorm" and hit enter

Answer 9

ok

Answer 10

now type in

0.08, -6, 8)

then hit enter

Answer 11

The general format is

invNorm(p, mu, sigma)

where p is the probability (or area under the curve), mu is the mean and sigma is the standard deviation

Answer 12

here's more info: http://tibasicdev.wikidot.com/invnorm

Answer 13

got it thank you! had no idea you could solve stat probs on a calc like that
thanks again

Answer 14

yw, yes it's very cool since your calculator can do a lot