Question

How do you covert a Z-score into a percent? (Class: AP Statistics)

Answer 1

@e.mccormick

Answer 2

@agent0smith

Answer 3

Convert*

Answer 4

definition of z-score?

Answer 5

a score's relationship to the average.
For example, I need to find a grade based on the normal model.
The given z-score is 2.2

Answer 6

Correct. The z-score is 2.2

Answer 7

I'm actually looking for an actual percent. I think the answer is supposed to be like 99%, but I'm not sure how to arrive at it.

Answer 8

two-sided or one-sided?

Answer 9

You have to use z tables... they are how you find the percentage.

Answer 10

one second

Answer 11

my teacher never covered what one or two sided would mean, so I'm not 100% sure.

These are the answers, but I can't arrive at these answers:
https://answers.yahoo.com/question/index?qid=20081012174422AAsmXyc

Answer 12

like it was stated, you need your table

Answer 13

the mean is 50 for the normal model. I'm assuming the standard deviation is 10. We used a calculator rather than a table. TI-84

Answer 14

This would be so much easier if you posted the question. You can't work out a % without knowing whether it's one or two sided, and also some context as to know which side of the z score to look at.

Answer 15

That's all that we know about the question. The mean has to be 50, with a S.D. of 10. We also know it follows the normal model. That's all it gives out.

Answer 16

https://www.youtube.com/watch?v=JY1Z57GZY3s

Answer 17

there are z-score to percentile calculators online

Answer 18

Yes, but the idea of asking the question is so that i can get the concept down for monday's quiz. I won't be able to use that on the exam.

Answer 19

there are different ways to calculate percentiles as well

Answer 20

Now, on my calculator, we have like 2nd STATS, and we could try InvNorm(, but it's not helping. I'm not sure if normalcdf( would work?

Answer 21

I've never used regular calculators, I've used statistical softwares

Answer 22

Maybe Agent Smith would know since he teaches in a class? We are learning with the TI-83/34 calc.

Answer 23

https://www.youtube.com/watch?v=rgNxd8n6vbk

Answer 24

I'm looking for percents, not percentiles, unfortunately.

Answer 25

I teach algebra 2 but haven't needed to calculate Z-scores yet. I might go over that later this year, but you can find it online. There are z score calculators online.

But you still need to know what you're finding... you don't just "convert" a z-score to a percentage, you use a z-score to find a percentage.

Answer 26

would it help to post the question?

Answer 27

Suppose that your statistics professor returned your first midterm exam with only a z score written on it. She also told you that a histogram of the scores was closely described by a normal curve. How would you interpret each of the following z scores?

a 2.2
b. 0.4
c. 1.8
d. 1.0
e. 0

Answer 28

Yes. As a brand NEW question.

Do not post it in here, enough space has already been wasted.

Answer 29

Alright, one minute.

Answer 30

Those all mean you need to find the area BELOW those particular z scores.

Eg. for the first, you'd find the percentage, then say "this score is higher than xx% of students in the class"