You must type this and all other homework assignments. Do not e-mail the assignment to me; turn it in early (at 322 Wolf) for a foreseeable absence, or turn it in late after an unexpected absence from class.
1. Every year, volunteers count birds in specific areas for the Audobon Society's Christmas Bird Count. You want to know whether the number of American black ducks (Anas rubripes) changed between 2013 and 2014 in Maryland. The number of American black ducks counted in each of 23 areas in Maryland is given below. Which test do you think would be most appropriate: a Student's t-test; a paired t-test; Wilcoxon's signed ranks test; or linear regression/correlation? Write a few sentences giving your reasons for choosing that test.
Location 2013 2014 Allegany County 1 11 Annapolis-Gibson Island 122 37 Bowie 51 30 Catoctin Mountain 0 8 Chesterville 754 239 Crisfield 423 119 Denton 7 19 Elkton 67 143 Jug Bay 657 477 Lower Kent County 1107 632 Oakland 51 50 Ocean City 844 759 Patuxent River 3 16 Point Lookout 6 8 Port Tobacco 57 54 Rock Run 116 49 Saint Michaels 47 32 Salisbury 39 62 Seneca 36 82 Southern Dorchester County 1441 397 Sugarloaf Mountain 71 57 Triadelphia Reservoir 24 91 Washington County 6 7
2. Analyze the data using whichever test you think is best. Use both a spreadsheet and SAS. Give the test statistic and P-value from the spreadsheet and from SAS. You mustprint your SAS program and your SAS output (the .lst file). If you can't get SAS to work, or you don't get the same P-value from SAS and the spreadsheet, you must e-mail me for help.
3. Now analyze the data using the other three tests; including what you did for question 2, you should have P-values from Student's t-test; a paired t-test; Wilcoxon's signed ranks test; and linear regression/correlation. You may use spreadsheets, web sites, or SAS for this. Give the P-values in a nice little table, and write a couple of sentences comparing the results of the tests.
4. Make a graph that summarizes the data from question 1 in what you think is the most effective way.
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This page was last revised October 28, 2015. Its URL is http://udel.edu/~mcdonald/stathw9.html