[OSOWLaf]

I am trying to find out - if I have a population of 17,920 with an average score of 1161, what is the population whose score is over 1,000?

[ebaines]

It's imposible to say. You need to know the standard deviation of the scores in order to determine this. If you know the standard deviation s, then the "Z-score" you're interested in is:

z = (1161-1000)/s

Then you can look up the percnetage of a normally distributed population whose z-score is within z of the mean. That gives you the percentage with scores from 1000 to 1161. In addition you know that 50% of the population scored higher than the mean of 1161, so you add 50% to this to ge the total percentage that got 1000 or better.