Statistics correlation help needed?

Question

I have an SPSS database with about 2000 students who took English Comp this past academic year. I also have their SAT scores. The correlation between the two is .381, which is significant at the .01 level. But how do use that to predict what a student with an SAT of X will get in English Comp? We are trying to determine if our SAT cut-score for entrance into English is too high or too low.

Answer 1

Hmmmm. I'm guessing you are a stats student, not on any admissions committee at all... OK so what you want to do in SPSS is a regression analysis using SAT as the independent variable and English Comp score as a dependent variable. That will allow you to get the coefficients for the model (i.e. slope and intercept). Once you have the coefficients, then you can use the model to predict English Comp grade from a given SAT score.

But all the other comments people made to your other post of this question are still valid comments - things stats people have to worry about in the real world. Good luck!

Answer 2

That's odd, two different people with exactly the same question!

Run a linear regression on the data with English grade as the y variable and SAT score as the x variable. The slope this regression yields will be the ratio of English grades to SAT scores, biased by the intercept value. the "r" value of the regression (calculated separately) will tell you how well the projection fits tha data |r| > 0.9 is generally considered a good fit.