Question

The Experiment. Does light environment have an influence on the development of color vision? The data are measurements on the relative abilities of Bluefin killifish from two wild populations to detect short-wavelength light (blue light in our own visible color spectrum). One population was a swamp, whose tea-colored water filters out blue wavelength, whereas the other population was from a clearwater spring. Fish were crossed and raised in the lab under two light conditions simulating those in the wild: clear and tea-stained. Sensitivity to blue light was measured as the relative expression of the SWS1 opsin gene in the eyes of the fish (as a proportion of the total expression of all opsins). Opsin proteins in eyes detect specific wavelength; SWS1 is so named because it is shortwave sensitive. The data are from a single individual from each of 33 families. Because the fish were raised in a common lab environment, population differences are likely to be genetically based, whereas differences between fish under different water clarity conditions are environmentally induced.

Pop1= Spring, Pop2= Swamp, Env1= Clear, Env2= Tea

Pop1_Env1	Pop1_Env2	Pop2_Env1	Pop2_Env2
0.16	0.08	0.09	0.06
0.11	0.13	0.09	0.07
0.12	0.07	0.08	0.08
0.11	0.12	0.10	0.08
0.08	0.12	0.12	0.10
0.09	0.05	0.06	0.03
0.14	0.06	0.13	0.00
0.16	0.11	0.80
		0.11
		0.07

1. How many factors are included in this experiment? Identify the factors and the levels within factors.

2. What type of experimental design was used?

3. Provide a statement of the full linear model.

4. How many null hypotheses are there?

Answer 1

1. There are 2 factors and each factor has two levels.

2. Two square factorial design is used.

4. There are three null hypothesis.