So lets say I have 2 data sets. Both sets contain various types of information about a person, including age as well as other factors relating to health (eg. cholesterol, blood pressure, etc)

The difference between the sets is that set 1 is sampled from the general population and set 2 is sampled from only healthy individuals with no risk factors.

Now say I do various bivariate correlations between age and the factors I am investigating. I found tests that have a valid correlation with age in both groups. I then plot the results for each test best fit line (note: That is one plot per set for each test).

How would I statistically compare the slopes of the best fit lines for each individual test, and not the tests as a whole?

I'm aware if I just make a table of the slopes for set 1 and set 2 and then do a chi-squared test, I could see how the sets compare to eachother as a whole, but I want to see if there is any way I can say:

In this one test, there is a very significant difference between the slope of the best fit line in set 1 and set 2.

I can't seem to wrap my head around this one, any help would be much appreciated!

Edit: If you know of a method that could be done using SPSS that would be even more helpful.

The difference between the sets is that set 1 is sampled from the general population and set 2 is sampled from only healthy individuals with no risk factors.

Now say I do various bivariate correlations between age and the factors I am investigating. I found tests that have a valid correlation with age in both groups. I then plot the results for each test best fit line (note: That is one plot per set for each test).

How would I statistically compare the slopes of the best fit lines for each individual test, and not the tests as a whole?

I'm aware if I just make a table of the slopes for set 1 and set 2 and then do a chi-squared test, I could see how the sets compare to eachother as a whole, but I want to see if there is any way I can say:

In this one test, there is a very significant difference between the slope of the best fit line in set 1 and set 2.

I can't seem to wrap my head around this one, any help would be much appreciated!

Edit: If you know of a method that could be done using SPSS that would be even more helpful.

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