Concept explainers
A study was conducted of genetic and environmental influences on cholesterol levels. The data set used for the study were obtained from a twin registry in Sweden [10]. Specifically, four populations of adult twins were studied: (1) monozygotic (MZ) twins reared apart, (2) MZ twins reared together, (3) dizygotic (DZ) twins reared apart, and (4) DZ twins reared together. One issue is whether it is necessary to correct for gender before performing more complex genetic analyses. The data in Table 8.17 were presented for total cholesterol levels for MZ twins reared apart, by gender.
Table 8.17 Comparison of mean total cholesterol for MZ twins reared apart, by gender
Note: n = number of people (e.g., for males, 22 pairs of twins = 44 people) the cholesterol levels within each sample consist of independent observation.
Suppose we want to use the procedure in Problem 8.49 using a two-sided test. State the hypotheses being tested, and implement the method. Report a p-value.
8.49 If we assume (a) serum cholesterol is
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Fundamentals of Biostatistics
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