Question

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. If a certain statistician has an IQ of 122, what percent of the population has an IQ less than she does?

Answer 1

@mathmate

Answer 2

how od I solve this??

Answer 3

Are you familiar with the normal distribution table?

Answer 4

um.. I think so

Answer 5

such as:
http://www.math.unb.ca/~knight/utility/NormTble.htm

Answer 6

yea.. its so confusing though! anyways what do I have to do?

Answer 7

normalize the IQ 122 as
\( Z=(X-\mu)/\sigma \)

Answer 8

so.. how/ what would I plug in?

Answer 9

Look up the table for Z, that will give you the percentage of the population with IQ 122 or less!

Answer 10

i don't understand? for what number of Z do i look up

Answer 11

Z=(X−μ)/σ that you calculated with X=122

Answer 12

ok.. and what abt the denominator symbol??

Answer 13

In statistics,
\( \sigma \) is the standard deviation, \( \mu \) is the mean.

Answer 14

so Z= (122-100) / 15???

Answer 15

.9279??? on the z-table? i got 93%?

Answer 16

Exactly!

Answer 17

yay that was my guess again!

Answer 18

i get it now! actually get the z-table! Thank u!

Answer 19

You can be more accurate by doing a little interpolation between .9279 and .9293

Answer 20

pls wait. i have to ask u another

Answer 21

is this an example of data gathering?
-finding the mean fasting blood sugar of diabetics

Answer 22

@mathmate

Answer 23

hello? are u there

Answer 24

If "mean fasting blood sugar" is a technical term, then you are gathering some technical information/data.
However, it does not seem to be, "fasting blood sugar" is, so you are just working to find the mean of some data before. In this case, this task is not data gathering.

Answer 25

ok.

Answer 26

yeah.. idk what that means either/ i don't THINK its a term...

Answer 27

fasting blood sugar is

Answer 28

but not with "mean'