Would anyone be able to help me out on how to compare percentages accross 2 different studies to explore if these percentages are significantly different? I am investigating the percentage of external/internal/no triggers that elicit involuntary memories in younger and older adults. I need to compare if the percentage of triggers I obtained with a young sample are different from another study looking at older participants using a very similar method to my own.

I am unsure how to run this analysis in SPSS and whether I regard these percentages as number of observations and enter these percentages accordingly? So far I have entered the data in the variable view in 3 rows. The first row corresponding to the type of trigger and giving it value labels (1=external; 2=internal, 3=no trigger), the second row corresponding to age (1=young, 2=older) and the third row was simply labelled frequency. Then, clicked on weigh cases by frequency. Finally, went on to crosstabs and dragged type of trigger in row and age in the column variable, ticked Chi-square in the statistics option and ran the analysis.

Is what I have done correct? Somehow it does not feel right as these are not the number of observations entered into SPSS but the percentage of each type of triggers.

I would very much appreciate if someone could help me out! Thank you!