U.S. Coins Project

Group Members

  1. __________________________
  2. __________________________
  3. __________________________

We are going to collect data about U.S. coins. Specifically, we will record the weight and mint for pennies (1983 to date), nickels (1946 to date), dimes (1965 to date), and quarters (1965 to date).

Part 1 - Data Collection

Each group should collect and weigh at least 10 coins of each type with a minimum of five from the Denver mint and five from the Philadelphia mint. The data will be combined into one file for the entire class to use. Make sure the years on the coins match the restrictions above.

The information should be entered into an Excel spreadsheet and saved on the U: drive in the folder U:\01\COINS. Give it a name that is unique to your group.

When you create the spreadsheet, row 1 should contain the labels for the columns. Label the first column "coin", the second column "mint", and the third column "weight". In the coin column, enter the value of the coin (1, 5, 10, or 25) rather than the name. In the mint column, abbreviate the mint as D for Denver or P for Philadelphia.

Part 2 - Report

Answer these questions using the combined class data. There are Minitab notes to help.

  1. Go to the US Mint website and get the claimed weights of each of the coins.
  2. Describe the who, what, where, when, why, and how of the data.
  3. Create side-by-side boxplots of the weights by the type of coin.
  4. Create a graphical summary of the weight of the coins for each type of coin. Describe the shape, center, and spread of the weights and how close the mean is to the claimed value from the US Mint.
  5. For each type of coin, are the weights normally distributed? Discuss how you can tell this from the histogram, normal probability plot, and Anderson-Darling test.
  6. The operator of a vending machine wants to accept 95% of all legitimate coins. What interval of weights should the machine accept for each coin? Does the claimed weight for each type of coin fall within the interval?
  7. For each type of coin, use our sample data to test the claim that US Mint makes about the weight.
  8. For each type of coin, test the claim that the Denver and Philadelphia mints produce the same weight coin.