-"adtype" (1 is print ad with testimonials, 2 is print ad without testimonials.)

-"AT1" which is "ad attitude immediately after watching ad"

-"AT2" which is "ad attitude after a week"

I would like to compere the ad attitudes. I would like to figure out whether the

**adtype**has a impact of the change of ad attitude, if yes, how strong.

I used dependent T-Test (AT1 and AT2) and found out that there is a significant difference, but I want to figure out the impact of adtype, so I used "split file by adtype", again I have significant difference between AT1 and AT2:

adtype ad with T:

AT1, means 5.9

AT2, means 5.0

adtype ad without T:

AT1, means 5.8

AT2, means 4.6

But still, I cannot see how the adtype influsses my results. What should I do then?

I consider to compute a new variable AT_change=AT1 - AT2, then a T Test with AT_change with adtype. I expect to see that in group ad with T, the change is smaller than group ad without T. Does this make sense?

Regards,