Baseballs

Since the birth of baseball in 1791, the mass of the ball has been believed to be five ounces.   The baseball is made up of four distinct layers; the very center is a cork ball about an inch in diameter with a thin rubber layer around it, the next layer is one hundred and twenty one yards of four- ply blue yarn, the third layer is forty five yards of three-ply white wool yarn, and finally one hundred and fifty yards of three-ply gray wool yarn.   The mass of all of these layers is supposed to add up to 5.00 ounces.   My partner and I became interested in the subject of baseball mass because we are very big fans of baseball and would like to know the true facts.   We believed that the true average mass of a baseball is not 5.00 ounces.
The data we collected is a simple random sample.   We collected our baseball by the dozen from six different athletic stores in our Atlanta area, two dozen came from separate dealerships in Alabama, another three dozen from separate stores in South Carolina, and one dozen from an online internet source.   All stores were randomly selected out of a total of fifty stores and Internet sites around the United States.   The stores were labeled alphabetically from 01-50 and using a random number table, we chose twelve numbers and used the properly labeled dozen of baseballs.   After our sample was collected we massed them using an enclosed scale so no outer air could affect the mass of the ball.   We massed the balls in ounces and to the hundredth decimal place.   Our null hypothesis was: The mass of a baseball is equaled to five ounces.   (u=5 oz.).   Our alternative hypothesis was: The mass of a baseball is not equaled to five ounces.   (u=5 oz.). [continues]

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