Is there a birth-month advantage to becoming a major league baseball player?

Is there a birth-month advantage to becoming a major league baseball player?
To answer this question we need to see how to distribution of birth month for major league
baseball players compares to the overall distribution of birth month for the national
population (that is our model)

a) We start by finding the expected counts… (Assuming the null hypothesis is true, how
many players in our sample would we expect to be born each month). Each expected
count is n*p (the total number of players)*(the national birth % from our model)

b) Make a table of that shows the Observed and Expected Counts for each month

c) We compute the chi-square test statistic as follows:

d) The c2 statistic follows the c2 distribution with n-1 degrees of freedom (n = # of categories)

To find the p-value you can use a c2  distribution calculator such as c2 cdf in  your TI