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 112, what percent of the population has a lower IQ?
A. 47%
B. 7%
C. 93%
D. 79%
E. 99%

Answer 1

@jim_thompson5910

Answer 2

Use z-score equation (point-mean)/standard deviation
112-100/15 = z-score of 0.8

Take this z-score and look at a z-score table (there should be one in the textbook you're using or you can just look up "z-score table" on google) to find the percentage of individuals that fall below this z-score.

Do this and tell me what percentage you find on the z-score table. I know the answer so I can tell you if you're right or not.

Answer 3

D?

Answer 4

Correct.

Answer 5

Thank you!- can you help me wit this other one?

Answer 6

Post it and I'll see if I can help or not

Answer 7

K

Answer 8

Sorry I can't help you with this one. I remember doing something like this but I took stats a couple years ago. Sorry.

Answer 9

Thanks

Answer 10

The correct answer to the question on IQ scores is 78.81%. Obviously the nearest choice is 79%.

Answer 11

Thank you!

Answer 12

You're welcome :)