Hi everyone,    I've got a question about combining and analyzing my data. I will try to explain it as good as possible:    I've got 4000 subjects, and for each subject 200 different variables with food intake. For each variable of food intake, I have three different values, which  I have to (separately) multiply with the variable to create new variables. So at the end, for each subject, I would have 600 more variables?    For example:                 potato subject 1: 50    Then I have to multiply the 50 g/d potato with 0,55 , 0,46 and 0,83 into three new variables. And repeat this for the 3999 other subjects. However, the next variable, bread needs to be multiplied with three values as well, but these values are different values as mentioned above..  And is there a procedure which I can use to do it faster?   At the moment I have a wide data set, but I guess I should make it a long data set. So I would have 3 observations for each subject, but the observations would be the same?    I really hope someone can help me.                ... View more