Feminizing faces study. Research published in Nature (August 27, 1998) revealed that people are more attracted to ‘‘feminized'' faces, regardless of gender. In one experiment, 50 human subjects viewed both a Japanese female and Caucasian male face on a computer. Using special computer graphics, each subject could morph the faces (by making them more feminine or more masculine) until they attained the ‘‘most attractive'' face. The level of feminization y (measured as a percentage) was measured.

(a) For the Japanese female face, y¯ = 10.2% and s = 31.3%. The researchers used this sample information to test the null hypothesis of a mean level of feminization equal to 0%. Verify that the test statistic is equal to 2.3.

(b) Refer to part a. The researchers reported the p-value of the test as p ≈ .02. Verify and interpret this result.

(c) For the Caucasian male face, y¯ = 15.0% and s = 25.1%. The researchers reported the test statistic (for the test of the null hypothesis stated in part a) as 4.23 with an associated p-value of approximately 0. Verify and interpret these results.