Assignment #8 - ANOVA Tukey's Post-Hoc tests - 2019

This assignment is a re-analysis of the data from Assignment #6, only now you have to complete the post-hoc analysis to determine which groups are different, what those estimated differences are, and the p-values associated with those differences.

Put answers to all the below questions in a word document.

Dataset #1 - For this dataset, you are conducting an experiment to see if bobwhite quail density (Y; quail/hectare) varies between habitat types (X). The habitat types examined are:  open pine, closed pine, prairie/pasture, and ag. Answer the following questions:

1. Run an ANOVA in R. Write a sentence describing the results (i.e., p-value). Typically, this sentence is something like "ANOVA indicated that at least two of the [x-variable] were significantly different from each other (p = [p-value])."

2. Plot the relationship between habitat types and quail density in R and paste the graph in your word document

3. Run a Tukey's HSD Post-hoc test in R. Using the standard language we have been using throughout the class, describe the estimated differences between Closed Pine and Ag and between Open Pine and Ag (be sure to include confidence intervals and p-values).

Dataset #2 - For this dataset, you are conducting an experiment to see how plant growth (Y; cm) is related to amount of fertilizer applied (X; grams). Answer the following questions:

1. Run an ANOVA in R. Write a sentence describing the results (i.e., p-value).

2. Plot the relationship between amount of fertilizer and plant growth in R and paste the graph in your word document

3. Run a Tukey's HSD Post-hoc test in R. Using the standard language we have been using throughout the class, describe the estimated differences between 2 and 10 grams of fertilizer and between 6 and 4 grams of fertilizer (be sure to include confidence intervals and p-values).

Dataset #3 - For this dataset, you are examining how deer kill rates (Y; deer killed / hunter) is related to hunting method (X; the variable is called 'Hunt'). Types of hunting methods considered in this study include rifle, bow, and Uzi. Answer the following questions:

1. Run an ANOVA in R. Write a sentence (like we discussed in class) describing the results (i.e., p-value).

2. Plot the relationship between hunting method and deer kill rates in R and paste the graph in your word document

3. Run a Tukey's HSD Post-hoc test in R. Using the standard language we have been using throughout the class, describe the estimated differences among all hunting methods (be sure to include confidence intervals and p-values).

4. compare the p-values and confidence intervals you get with the Tukey's Post-Hoc test to what you get from an lm. How are they different? Why are they different?