In Paul’s experiment participants were randomly assigned to four conditions. Open the file Paul​.sav and look at the variable “group”. Participants were shown a number of ads. One of the ads was a version of a film made by Paul himself, for a company called Job.nl. In the first group the ad was presented with a loud and supposedly irritating sound (…that of an alarm clock). The background color was a striking red. In the second, he presented the same ad with a more neutral white background. In the third, he showed the ad without the sound and with a red background, and in the last group the ad was presented without the sound and with a white background. Now, Paul’s idea was that the strikingness, (or irritation, one could say) might affect recall. So, the next day he contacted his participants by phone and asked them which of the ads they remembered. Take a look at his questionnaire. The first question simply pertains to recall, the second to cued recall, and the third was intended to assess what participants remembered of the content of the ads. Let us look at what the participants thought of the ads. Conduct two Chi-Square tests.

In the first, “group” should be the independent variable and use “postirri” as the dependent variable. “Postirri” is a nominal variable: a score 1 stands for choosing Paul’s ad as the most irritating ad, and 0 for choosing another. What do the results tell you? In the second Chi-square test you simply change the dependent variable; instead of “postirri” you investigate “posteffe”: a score 1 stands for choosing Paul’s ad as the most effective, and 0 for choosing another. Interpret the results. What do they tell you, in relation to the previous test you ran?