Hello, I am a new-starter of SPSS. I have around 100 participants, each having measurement from both device A and device B (i.e. each participant has one measurement from device A and another measurement from device B). I would like to create a conversion equation and validate it. My plan is to divide them into two groups randomly (each group has 50 participants). One group is used to derive the conversion equation between device A and device B. Another group is used to validate the equation.

I would like to ask how do I (i) find the conversion equation and (2) validate the equation in SPSS. Thank you very much for your help in advance.

There are many ways to assess the relationship between two variables. If both are scale measurement level, linear regression is a good place to start. But you should look at residuals to check whether the relationship is linear. If one or both are categorical, there is more to say, but I'll leave that until hearing that you have this issue.

Thank you very much for your help. My variables are continuous. Thank you again.