Statistical Ecology
Stat 555, Fall 2009
Assignment
Models in Analysis of Variance and Nested ANOVA
Problem 1: Model II ANOVA
Purpose: To explore variance components of an experimental design using model II ANOVA
Data: An investigator was interested in the range of spatial variation in Molokini crater on Maui, Hawaii. Three 50m transects were established at each of 15, 40 and 60 ft depths in three locations in Molokini (east, west, middle). Photographs were taken of 36 quadrats along each transect and the percent cover of coral estimated using a random point method with 50 points.
Test the data for the assumptions of ANOVA and transform if necessary
Analyze the collected data using a model II ANOVA
Calculate variance components for each significant factor
Interpret the results.
Data file: molokini_model2.mpj
Problem 2: Nested ANOVA
Purpose: A researcher was interested in the effects of a compound (C_217) and the compound plus sugar (C_217+S) on the glycogen content in liver cells. However, she realized glycogen varied naturally among different individuals, among different cells within the liver, and among different preparations made with the same liver cells, so she designed a nested experiment to test for the effects of the two compounds on liver cell glycogen content.
Data: Accordingly, she used three treatments:
Control (injected with saline)
C_217 (injected with compound 217)
C_217+S (injected with compound 217 plus sugar)
For each treatment she used two rats; for each rat she made three preparations from the liver; from each preparation she took two readings in a refractometer to estimate glycogen content.
3. Assignment
Test the data for the assumptions of ANOVA and transform if necessary.
Analyze the data using a nested ANOVA
Estimate the variance components for the random factors
Interpret the results.
This assignment is due next Wednesday, Sept. 16, 2007, in class.