Question

The gene ACTN3 encodes a protein that functions in fast-twitch muscles. People can be classified according to which genotype of this gene they have, RR, RX, or XX, and also according to which genetic allele they have, R or X. The study¹ described here, examines the association between this gene and different subgroups of the population. All participants in the study live in Australia. The earlier exercises only included the control group.

Testing Genotypes for Fast-Twitch Muscles
The study on genetics and fast-twitch muscles includes a sample of elite sprinters, a sample of elite endurance athletes, and a control group of non-athletes. Is there an association between genotype classification (RR, RX, or XX) and group (sprinter, endurance, control group)? Computer output is shown for this chi-square test. In each cell, the top number is the observed count, the middle number is the expected count, and the bottom number is the contribution to the chi-square statistic.


(a) What is the expected count for non-athletes with the RRgenotype? For this cell, what is the contribution to the chi-square statistic?
Expected count=.
Contribution to the chi-square statistic=.

(c) What is the chi-square test statistic? What is the p-value? What is the conclusion of the test?
chi-square statistic=
p-value=

(e) Which genotype is most over-represented in sprinters?
Which genotype is most overrepresented in endurance athletes?

Answer 1

GOD Rk 920 M3. 214.15 Rp xX total 130 13.0 .316 sprind to구 S3 3S- 28 End 8.901.043 Enduran 20 L-40 /9니 96 Total 24 3 362 433 1 32 is 35-28. (or- Cr) most sepne.sn ded is