Managing for Quality and Performance Excellence 10th Edition by James Evans ,William Lindsay

Exercise 52

The Thomas Jefferson Nickel was first produced in 1938. The United States Mint produces all U.S. coins at their Philadelphia, Pennsylvania, and Denver, Colorado, facilities. According to the U.S. Code, a nickel has a nominal specification weight of 5.00 grams and a tolerance of +/? 0.194 gram. A study was conducted for nickels produced from 1960 through 2013. The data were gathered by obtaining three randomly selected rolls of nickels from a bank clerk. Any nickels produced before 1960 may have significant wear and, therefore, were removed from the sample.
Each nickel was weighed using a digital scale calibrated to read grams to two decimal places, in increments of 0.01 grams. The scale was placed on a flat, balanced surface. To ensure the repeatability of the measuring process, an "X" was drawn on the platform of the scale, indicating where each nickel would be placed, and each nickel was weighed five times to verify the result. The weight was checked by a second person to verify reproducibility. Using the same measuring instrument and process, each nickel was again measured five times. The raw data are provided in the Data Set 1 worksheet in the Excel file Nickel Experiment Data.
Compute descriptive statistics and a frequency distribution and histogram for the weight of the overall sample and by the mint where the nickels were produced. Are there any significant differences by mint?