# B explain why you selected this test 1 mark there are

• 21
• 100% (8) 8 out of 8 people found this document helpful

This preview shows page 10 - 14 out of 21 pages.

B. Explain why you selected this test [1 mark]
C. Indicate the null and alternative hypothesis (be mindful of direction in the test) [1 mark]
D. Name the appropriate test statistic (e.g., Chi-square score) (You do not need to find its value.) [1 mark]
E. The following R output shows the results of the statistical test. Based on this output, what is the observed test score for this test? [1 mark]
F. Explain in words what the VALUE of the observed test score means for this test in terms of a ratio of variances. [1 mark]
G. What is the critical test score for this test assuming an alpha value of 0.05? [1 mark]
H. Based on the observed and critical test scores, what is your statistical AND scientific conclusion? [1 mark]
11
22) You have been asked by a regional conservation authority to design a study to evaluate the risk that a tick will bite someone walking at one of the parks. They have provided you enough money to survey 15 parks out of the 60 that are in the region. Your plan is to spend a day at each of the selected parks and survey all the people leaving the park to assess whether a tick bit them or not. You will then calculate the proportion of people bitten for each park sampled. A. Indicate the survey design that is most appropriate to use for this question. [1 mark] [cluster design.] B. Indicate the observation unit. [1 mark]
C. Indicate the sampling unit. [1 mark]
D. Indicate the statistical population. [1 mark]
12 23) The figure below shows an interaction plot from a 2-factor ANOVA. The data are bacterial densities of Pasteuria ramosa as a function of different types of soil (media A, B, C, D and E) and bacterial strain (strain1, strain 2). Strain 1 is shown as a solid line and strain 2 as a dashed line. Draw on this plot what the line for strain 2 (dashed line) would look like if the two factors of soil type and bacterial strain were purely additive. [1 mark] Based on this, does the impact of bacterial strain change depending on the type of soil? Explain your answer. [2 marks] [Since the lines are distinctly non-parallel, it indicates that the bacterial strain has an impact on Pasteuria ramosa density, and that the effect depends on the type of media.
13