You are a researcher for a biotechnology company You would l

You are a researcher for a biotechnology company. You would like to test the independence of the relationship between types of plants and different fertilizers. You decide to test five different kinds of fertilizer on three different kinds of plants. You plant in separate plots every combination of plant and fertilizer. You then measure the plants and conduct a Contingency Table Test on the results. What is the correct Degrees of Freedom to use in the test?

Question 5 options:

8

15

6

11

10

12

Solution

Note that

df = (a - 1)(b - 1)

where a and b are the number of categories for each variable.

Here, a = 5 for fertilizers,
b = 3 for plants.

Thus,

df = (5 - 1)(3 - 1) = 4 * 2

df = 8 [ANSWER, OPTION 1]