6.46Following the March 24, 1989, grounding of the tanker Exxon Valdez in Alaska, approximately 35,500 tons of crude oil were released into Prince William Sound. The paper "The Deep Benthos of Prince William Sound, Alaska, 16 Months After the Exxon Valdez Oil Spill" (Feder and Blanchard, 1998) reports on an evaluation of deep benthic infauna after the spill. Thirteen sites were selected for study. Seven of the sites were within the oil trajectory, and six were outside the oil trajectory. Collection of environmental and biological data at two depths, 40 m and 100 m, occurred in the period July 1-23, 1990. One of the variables measured was population abundance (individuals per square meter). The values are given in the following table.

Develop a plot to help communicate your conclusions in 6.46a. Make a PDF (importing a PNG into Word may be easiest, or from RMarkdown if you are using RStudio) that includes your image and a short caption to help interpret your figure. Follow the "glamour of graphics" to present a visually appealing, informative product. If you include this image in the file you use to submit your homework, please also submit the file separately here so that I can grade it separately.

A few requirements: - Submit your product in PDF format. Include a .R file that contains all code necessary to produce the plot(s) and analyze the data. Include your data file (probably .csv). Your plot(s) must be reproducible! - The figure you produce, supported by the caption, must clearly communicate your findings from exercise 6.46a. - You may not use the default layout. - You may not use the default colors. - You may not use the default font. - Any labels (axis labels, titles, tick mark labels, etc.) must be legible.

Within Oil Trajectory Outside Oil Trajectory Site 1 2 3 4 5 6 2 3 5 6 Depth 40 m 5,124 2,904 3,600 2,880 2,578 4.146 1.048 1.336 394 7,370 6,762 744 1,874 Depth 100 m 3,228 2,032 3,256 3,816 2,438 4.897 1,346 1,676 2,008 2,224 1,234 1,598 2,182 a. After combining the data from the two depths, does there appear to be a differ- ence in population mean abundances between the sites within and outside the oil trajectory? Use a - .05. b. Estimate the size of the difference in the mean population abundances at the two types of sites using a 95% confidence interval. c. What are the required conditions for the techniques used in parts (a) and (b)? d. Check to see whether the required conditions are satisfied