Question

Find the value of z such that approximately 8.32 of the distribution lies between it and the mean.

I have worked it out, just wanting someone to check it over:
8.32%=0.0832
0.5000-0.0832=0.4168
z=0.4168



@ap statistics

Answer 1

you're on the right track, but you now need to use the inverse CDF function to find the z value (what you have is the area, not the z value)

Answer 2

often, this function is called invnorm

Answer 3

well how do I do that?

Answer 4

what kind of calc do you have?

Answer 5

TI-30XA

Answer 6

hmm don't think they support normal distributions

Answer 7

your best bet is to use either a TI 83 or 84 or you can use wolfram alpha

Answer 8

http://www.wolframalpha.com/input/?i=invnorm&f1=0.4168&x=0&y=0&f=NormalProbabilities.pr_0.4168&a=*FVarOpt.1-_***NormalProbabilities.pr--.***NormalProbabilities.x--.**NormalProbabilities.l-.*NormalProbabilities.r---.*--&a=*FVarOpt.2-_**-.***NormalProbabilities.mu--.**NormalProbabilities.sigma---.**NormalProbabilities.pr---

Answer 9

click the link above to see the z value which generates an area/probability of 0.4168

Answer 10

I havent had to use a different calculator.

Answer 11

im in elementary statistics

Answer 12

it turns out that the value of z is z = -0.21

Answer 13

oh, well let me check to see if 30XA supports invnorm then

Answer 14

I have never heard of invnorm.

Answer 15

they might use another name for it

Answer 16

ok, your calc does support it

Answer 17

hit 2nd, then stat-reg/dist

Answer 18

just do it or put a number in?

Answer 19

then go to #3 (invnorm)

Answer 20

then type the number in after that

Answer 21

yes you enter the number after you've selected invnorm

Answer 22

nope I do not have a stat button.

Answer 23

do you have a probability button?

Answer 24

or maybe a dist button?

Answer 25

which looks like what?

Answer 26

I dont have to do all this stuff, I am used to just finding a number then adding or subtracting to it.

Answer 27

oh so you're using a table?

Answer 28

yeah.

Answer 29

thats where the other number came from.

Answer 30

ok so what you were looking at was the table of areas given a certain z value then

Answer 31

you need to use this table to find the z value which gives you an area of 0.4168

Answer 32

yes.
but the other number in the percentage turned into a decimal.

Answer 33

0.1591

Answer 34

that's the z value you found that corresponds to 0.4168 ?

Answer 35

well 0.41

Answer 36

i see

Answer 37

its actually more like -0.21

Answer 38

the negative turns into a positive, there is no negatives in the table

Answer 39

ok then 0.21

Answer 40

how did you get that?

Answer 41

I'm using a calc, but let me find a table real quick

Answer 42

I give up on this question!