Random Samples and Histograms: Distribution of Signal Errors in Project

Making a file like AuctionFocus.xls for your team’s project

1. Put your team’s data in the Data page of AuctionFocus.xls.

2. Calculate the mean of the 20 historical leases. Use =Average(…)

3. Calculate the error in each signal for your team’s data. If you adapt AuctionFocus.xls, make sure you adapt it to include all your data and nothing else. (You have a different amount of data than the class project.)

4. How many errors do you have?

5. Calculate the mean of all your errors.

6. Does your answer to #5 support the assumption that the geologist were on average correct?

Making a Histogram

• Find max and min of data

• Calculate “nice” bin limits (often about 10 bins in all) and type them in a columns.

• Use Data Analysis/Histograms; select Chart Output

7. Make a frequency histogram of the lease values. Use 5 bins as there is not much data. Start at 160 and make the bins 35 in width.

Making a Special Histogram to Approximate a PDF: Area is 1

This histogram will have bars of heights which make its area equal to 1.

• Make a frequency table, as above

• Change the heights of your bars by computing relative frequencies. (This means divide the

frequencies by the total number of pieces of data.)

• Divide the bars by the width one bin. (See AuctionFocus.xls, Densities page.)

• Make a bar graph

• Arrange to get the labels on each column correct. (See AuctionFocus.xls, Densities page.)

8. Use the data you found in #7 to make a histogram approximating the pdf of the lease values.

Make a Histogram Approximating the PDF of Your Errors

9. Find the maximum and minimum of your errors.

10. Calculate the bin width for 11 bins. This should be a “nice” number.

11. Calculate “nice” bin limits arranged around 0, as in AuctionFocus.xls.

12. Make a histogram approximating the pdf of your team’s errors.

13. Make a line graph approximating your pdf.

Hang on to this Excel file. It is the first part of the solution to your project, so it is valuable! (and it is part of your homework due this Wednesday).