Question

Do you view a chocolate bar as delicious or as
fattening? Your attitude may depend on your gender.
In a study of American college students, Rozin, Bauer,
and Catanese (2003) examined the importance of food
as a source of pleasure versus concerns about food
associated with weight gain and health. The following
results are similar to those obtained in the study. The
scores are a measure of concern about the negative
aspects of eating.
Males Females
n  9 n  15
M  33 M  42
SS  740 SS  1240
a. Based on these results, is there a significant
difference between the attitudes for males and for
females? Use a two-tailed test with   .05.
b. Compute r2, the percentage of variance accounted
for by the gender difference, to measure effect size
for this study.
c. Write a sentence demonstrating how the result of
the hypothesis test and the measure of effect size
would appear in a research report.

Answer 1

a. Divide SS by the number of scores to get variance.

Standard deviation = square root of variance

Z = (mean1 - mean2)/standard error (SE) of difference between means

SEdiff = √(SEmean1^2 + SEmean2^2)

SEm = SD/√n

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.