The grading rubric for this assigment can be found through the following link: Grading Rubric for the Projects
Problem: In January 2006, Dan Donato and co-authors J.B. Fontaine, J.L. Campbell, W.D. Robinson, J.B. Kauffman, and B.E. Law published a short Science article (vol 311, p.352) reporting, essentially, that measures of seedlings after a natural fire in Oregon indicated that it seemed better for seedlings for logging companies not to salvage log after a fire. That is, there was a greater decrease in the number of seedling in the logged areas between 2004 and 2005 than in the unlogged areas. The fire that occurred in 2002 was named the Biscuit fire. The salvage logging that occurred took place in between the recording of seedling numbers given in the table below. Thus, 2004 numbers were before logging occurred and 2005 numbers were after logging occurred in the plots where it occurred.
Later in 2006, after his article was published, Dan was called to testify in front of a congressional committee, in part to defend his statistical analysis. Dan was a young graduate student at the time. Congressman Baird disputed Dan's statistical techniques claiming that other techniques, namely 2-sample t-tests, were more appropriate for the analysis of these data and indicated no significant difference in logged versus unlogged areas.
Analyze these data yourself and write a report, either defending Dan's and his co-author's claim that logging hurt seedling production or defending Congressman Baird's contention that there is no significant difference and that salvage logging should be allowed to continue. Think about what the appropriate null and alternative hypotheses should be - these are formed before seeing the data. Note that before these data were published, it was widely believed that logging should be beneficial for seedling rejuvenation. Defend your choice of statistical test - preferably in language that a congressman or a forestry graduate student could understand.
Plot seedlings_2004 seedlings_2005 treatment 1 298 164 logged 2 471 221 logged 3 767 454 logged 4 576 141 logged 5 407 217 logged 6 1534 224 logged 7 2423 349 logged 8 1697 1388 logged 9 1137 646 logged 10 288 220 unlogged 11 622 747 unlogged 12 300 260 unlogged 13 888 584 unlogged 14 1448 1566 unlogged 15 1425 626 unlogged 16 2349 1924 unlogged