Study examines the ACTN3 genetic alleles R and X, also associated with fast-twitch muscles. Of the people in this sample, were classified R and were classified X. Does the sample provide evidence that the two options are not equally likely Conduct the test using a test for a proportion, using where represents the proportion of the population classified R. Include all details of the test.

Yes, the samples of R and X of α-actinin-3 (ACTN3) R577X polymorphism provided evidence that the two options are not equally likely Conduct the test using a test for a proportion, using where represents the proportion of the population classified R.  

Explanation: On one hand, from the reports of the following researcher; (North et al., 1999), (Gomez-Gallego et al., 2009; Yang et al., 2003), (Vincent et al., 2007) and (Kikuchi et al., 2014) supported that α-actinin-3 (ACTN3) R577X polymorphism is associated with muscle fibre type for power, elite performance, important for anchoring actin and plays a regulatory role in coordinating muscle fibre contractions.  

On the other hand, researchers such as Erskine et al. (2014), on 51 untrained healthy Caucasian males, Delmonico et al. (2007) studied an association between the ACTN3 genotype and training responses in a large Caucasian population of 157 relatively healthy sedentary Caucasian men and women, Gentil et al. (2011) detailed the outcomes of 141 young men, Pereira et al. (2013) reported the influence of ACTN3 polymorphisms and ACE I/D alone and in combination with muscle strength, power, and functional phenotype in older Caucasian women following 12 weeks of high-speed power training and Lima et al. (2011), conducted a study of 246 women (age 66.7 ± 5.5 years) agreed that in healthy relatively young sedentary Caucasians that both the ACE I/D and ACTN3 R577X polymorphisms (alone or in combination) were found to be associated in the baseline muscle strength, muscle strength resistance training, thickness of muscles and athletic status.  

However, the X allele, which is associated with the absence of ACTN3 protein, is suggested to impair the performance of high force/speedy muscle contractions. Using (Gentil et al., 2011) as the control experiment, the sample of 141 men performed two resistance training sessions per week for 11 weeks. The Participants were tested for 1-repetition maximum (1RM) bench press, knee extensors peak torque and knee extensors muscle thickness at baseline and after the training period. Consequently, genotype distribution was 34.4% for RR, 47% for RX, and 18.6% for the XX genotype. Drawing an inference from the to the results, the R577X polymorphism at ACTN3 was not associated with baseline muscle strength or the muscle strength response to resistance training. However, only carriers of the R allele showed increases in muscle thickness in response to training.  

Exceptions: (Clerkson et al, 2005) posited that women with RR genotype had a greater increase in muscle power than the men while in Delmonico et al (2007) disputed that claim by saying that women with XX genotype have greater relative responses than men.