12. Heavenly Pennies, Revisted

For this exercise you will need to retrieve the class data for the weight of many pennies. You will need to save this file to your disk. This is a new Excel file, open it under file, open. You can sort the data by minting year using the following instructions:

  1. Highlight all of the data, both columns should be selected.
  2. Go to the menu and select "sort" from the "Data" column.
  3. This will open a dialog box that will ask what column to sort first. If your minting date values are in column A, then select A and hit OK. This will sort the data by year.

Next, you will want to find average the average value for pennies minted before 1982 and the average value for pennies minted after 1982. You can do this with the following procedure:

  1. Click on a cell where you want the average to go.
  2. Click on the fx key on the tool bar.
  3. Select Statistical functions from the left hand list.
  4. Select AVERAGE from the right had list.
  5. Hit the next button.
  6. Highlight the data that you want to average, i.e. all of the masses for pre 1982 pennies.
  7. Hit the next button.
  8. You should have an average value in the cell where you started.
  9. Repeat this for the post 1982 pennies.
A standard deviation for each of these sets of data can be calculated using the same procedure and selecting STDEV from the right hand list in the fx dialog box. An average deviation can also be calculated by selecting the AVEDEV from the right had list in the fx dialog box.

Make a table that has

  1. Title
  2. Labels for the data columns
  3. Average value for the mass of pre 1982 pennies
  4. Average value for the mass of post 1982 pennies
  5. Standard deviation and average deviation for both of the above averages

Make a graph of

  1. Mass of a penny vs minting year.
  2. Label the graph with a title and axis labels.
Include a purpose, procedure and a conclusion along with above described results. In your conclusion restate the average mass values, standard deviations and average deviations. What is the difference between the meaning of standard deviation and average deviation. Is one more significant than the other? What is the difference between accuracy and precision?

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