5lb CHAP 22 #37 - Percentile/standard deviation

[yiyang07]

CHAP 22 5lb #37

Test outcome is between 151-200 inclusive. percentile of 400 tests are calculated and divide into percentile.

A. minimum number of integers between 151 and 200 inclusive that include more than 1 percentile.

B. minimum number of percentile groups that correspond to a score of 200.

If everyone get 157. Then 157 become 1-100 percentile. However, in this case isnt 200 still considered 100 percentile as well? I dont understand why it would be considered as nothing.

Its like taking a standardized test while no one may get perfect score, the perfect score is still considered 99%?

Is it because in this case we know all the possible outcome? If everyone get 157 then 200 would be outside of the range and assigned no percentile?

[tommywallach]

Hey Yiyang,

Yeah, your explanation of this is already really good!

The smallest number of different scores there could be is 1 (i.e. everyone scores a 160). In that case there would be 1 score that includes more than 1 percentile.

The most number of different scores there could be is 50, because an equal number of people could get each score (and there are 50 of them, from 151-200), which would make each score worth 2 percentile points.

This means column A is 1.

For column B, we don't know if anybody scored 200. If nobody scored 200, then no percentile groups would apply to that score (you already said this!).

Hope that makes sense!

-t