Convert the IQ to a z score. Read to the z at the left, get z of 1.65 7. We already found that in the previous problem, and it was a z of 1.65 . In .03 column, find 49.01. There are some disadvantages to z scores of course.
Advantage is they can be manipulated arithmetically.
So they are cumbersome. A standard score with a mean of 50 and s of 10 is popular with publishers of standardized tests, and such standard scores are called T scores . Remember that the standard score we are using is a T score. The T score is 30 and this comes from a distribution that has a mean of 50 and a s of 10. The reason we spend so much time on z scores, is that I think they are the best way to understand the normal curve.