Question: In the Preview for this chapter, we discussed a study that examined the effect of eye-spot patterns on the behavior of moth-eating birds (Scaife, 1976). The birds were tested in a box with two chambers and were free to move from one chamber to another. In one chamber, two large eye-spots were painted on one wall. The other chamber had plain wall. The researcher recorded the amount of time each bird spent in the plain chamber during a 60-minute session. Suppose the study produced a mean of M = 37 minutes on the plain chamber with SS = 288 for a sample of n = 9 birds. (Note: If the eye spots have no effect, then the birds should spend an average of μ = 30 minutes in each chamber.)

a. Is this sample sufficient to conclude that the eye-spots have a significant influence on the birds’ behavior? Use a two-tailed test with α = .05.

b. Compute the estimated Cohen’s d to measure the size of the treatment effect.