Question: Is the researcher cheating?

You become suspicious when a genetics researcher randomly selects group s of 20 newborn babies and seems to consistently get 10 girls and 10 boys. The researcher explains that it is common to get 10 girls and 10 boys in such cases.

a. If 20 newborn babies are randomly selected, how many different gender sequences are possible?

b. how many different ways can 10 boys and 10 girls be arranged in sequence?

c. What is the probability of getting 10 boys and 10 girls when 20 babies are born?

d. Bases on the preceding results, do you agree with the researcher’s explanation that it is common to get 10 boys and 10 girls when 20 babies are randomly selected?