Example: Analysis of Associations 2

You are charged with helping your neighbors answer an important question. They are farming trout in a series of three ponds, each had been stocked at the beginning of the season with 1100 fish. Jerry and Darleen would like to know whether the conditions in these ponds are equal or whether some ponds are more favorable to raising trout than others. They are about to drain the ponds and expect to collect 1000 individuals from each pond.

Exercise 1: Are these measures related? - Part 2

1. Download the file "Yield.txt". Save the content of the file as a TEXT file and you will be able to view and edit it with any text editor, such as BBEdit. Note that there are 11 pairs of measures (continuous) representing the yield that farmer Bob obtained from using a certain amount of fertilizer. The first line contains the names of the two variables, "Yield" and "Fertilizer".
2. Consider the existence and direction of causality between these two variables. Explain your considerations.
3. Prepare a scatter plot of the data
4. Perform a linear regression analysis. Based on this analysis what do you conclude about the association between the two variables?
5. It appropriate, calculate the Coefficient of Determination for this relationship.
6. Using G-power (installed in the computer lab) conduct a post-hoc power analysis on the regression analysis for the "Yield.txt" data set. What level of power is returned?