40f9 L A [\\J N_. II no. (a) What is the sample size? n: (b) What is the observed number of people with the variant RR for this gene? What is the expected number of people in this group under H0 ? Observed = Expected = (c) Which variant contributes the most to the chisquare statistic? O For this variant, is the observed value greater (gin or less than expected? 4 of 9 - / 12 E . . . Expected = (c) Which variant contributes the most to the chi-square statistic? C For this variant, is the observed value greater than or less than expected? C for the Greater than Less than (e) What is the p-value? p-value = HI Do the assumed proportions appear to be4 of 9 - /12 WIN - . . . Genetic Variation in Fast-Twitch Muscles Chi-square tests are common in genetics. A gene called ACTN3 encodes a protein which functions in fast-twitch muscles. People have different variants of this gene, classified as RR, RX, or XX. Computer output is shown for testing whether the proportions in these categories are 0.25, 0.5, and 0.25, respectively. The observed counts come from a study conducted in Australia. Chi-Square Goodness-of-Fit Test for Obse Test Category Observed Proportion Expecte RR 130 0.25 109 RX 226 0.50 218 XX 80 0.25 109 N DF Chi-Sq P-value 436 2 12.0550 0.0024 of 9 - /12 E . . . Expected = (c) Which variant contributes the most to the chi-square statistic? C greater RR RX XX or the test? Degree of Freedom = (e) What is the p-value? p-value = Do the assumed proportions appear to be40f9 -/12 ;= txpected = (c) Which variant contributes the most to the chisquare statistic? 0 For this variant, is the observed value greater than or less than expected? 0 (d) What are the degrees of freedom for the test? Degree of Freedom = (e) What is the pvalue? p-value = o the assumed proportions appear to be 4 of 9 - /12 E . . . Do the assumed proportions appear to be accurate? 1Yang, N., et al., "ACTN3 genotype is associated with human elite athletic performance," American Journal of Human Genetics, September 2003; 73:627-631. e Textbook and Media4 of 9 - /12 E . . . HI Do the assumed proportions appear to be accurate? C Yes 1 ssociated No e." A eptember 2003; 73:627-631. e Textbook and Media