Results

Independent Samples T-Test

Task 5: Based on the output below, U = 105.5, and we had 18 people who listened to each singer (n₁ = n₂ = 18). The effect size is, r_rb = -0.35. This represents a medium effect: when listening to Brian Johnson people proposed higher offers than when listening to Bon Scott, suggesting that they preferred Brian Johnson to Bon Scott. However, the 95% confidence interval indicates quite some uncertainty about this effect size and is located close to 0, so we probably need to collect more data to make any meaningful statements about the true difference in offers. We could report something like (note that I’ve quoted the mean ranks):

People listening to Bon Scott (mean R = 15.36) did not make significantly different offers to those listening to Brian Johnson (mean R = 21.64), U = 105.5, p = .067, r_rb = −0.35 (95% CI [-0.63, 0.02]).

Task 6: The output below tells us that U = 236, and we had 18 people who listened to each singer (n₁ = n₂ = 18). The effect size is r_rb = 0.46. This represents a fairly strong effect: looking at the mean ranks in the output below, we can see that people accepted lower offers when listening to Brian Johnson than when listening to Bon Scott. We could report something like (note that I’ve quoted the mean ranks):

The minimum acceptable offer was significantly higher in people listening to Bon Scott (mean R = 22.61) than in people listening to Brian Johnson (mean R = 14.39), U = 236, p = .014 suggesting that people preferred Brian Johnson to Bon Scott. This effect was moderately strong, r_rb = 0.46 (95% CI [0.11, 0.7]).