Lipids provide much of the dietary energy in the bodies of infants and young children. There is a growing interest in the quality of the dietary lipid supply during infancy as a major determinant of growth, visual and neural development, and long-term health. An article reported the following data on total polyunsaturated fats (%) for infants who were randomized to four different feeding regimens: breast milk, corn-oil-based formula, soy-oil-based formula, or soy-and-marine-oil-based formula. (Use i= 1, 2, 3, and 4 respectively.) Sample Regimen Sample Size Sample Mean Sample SD
Breast milk 15 42.9 1.3
CO 17 43.1 1.5
SO 8 43.7 1.2
SMO 14 43.9 1.2
What assumptions must be made about the four total polyunsaturated fat distributions before carrying out a single-factor ANOVA to decide whether there are any differences in true average fat content?
a. The distribution of polyunsaturated fat percentages for each of the four regimens must be uniform with equal variances.
b. The distribution of polyunsaturated fat percentages for each of the four regimens must be normal with unequal variances.
c. The distribution of polyunsaturated fat percentages for each of the four regimens must be normal with equal variances.
d. The distribution of polyunsaturated fat percentages for each of the four regimens must be binomial with unequal variances.