I need help with this

18. NHL - Birthdays: It has been observed that a large percentage of National Hockey League (NHL) players have birthdays in the rst part of the year. It has been suggested that this is due to the cutoff dates for participation in the youth leagues those born in the earlier months are older than their peers and this advantage is amplied over the years via more opportunities to train and be coached. Of the 512 players in the 2008/2009 NHL season, 159 of them were born in January, February, or March. (a) Assume that 25% of birthdays from the general population occur in January, February, or March (these actually contain 24.7% of the days of the year). In random samples of 512 people, what is the mean number of those with a birthday in January, February, or March? (b) Recognizing that 159 of the 512 NHL players were born in the rst three months of the year. Does this suggest that there is something unusual happening