14. Many animals, including humans, tend to avoid direct eye contact and even pa

Question

14. Many animals, including humans, tend to avoid direct eye contact and even patterns that look like eyes.Some insects, including moths, have evolved eye-spot
patterns on their wings to help ward off predators.Scaife (1976) reports a study examining how eye-spot patterns affect the behavior of birds. In the study, 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 walls. 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 a= .05.
b. Compute the estimated Cohen’s d to measure the size of the treatment effect.
c. Write a sentence that demonstrates how the outcome of the hypothesis test and the measure of effect size would appear in a research report.

Explanation / Answer

A)

= .05 n=9 M=37  µ = 30 t critical= 2.306

first find

s= (ss/n-1) = (288/8)= 6

second find

sm= s/n = 6/9= 2

third t score

t=((M-µ)/sm)= ((37-30)/2) = 3.5

so you are able to reject the null hypotheses

therefore you can conclude eye sight has a significant influence on the behavior of a bird

B)

s=6 (from above)

d= ((M-µ)/s)

d= ((37-30)/6)= 7/6 1.16

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