Question

Use this information to answer the next three questions.

A poultry specialist is conducting an experiment to determine whether the mean cholesterol content of egg yolks is affected by adding certain chemicals to the feed given to the hens laying those eggs. The 120 laying hens available for the study will be randomly allocated to three groups. Each group of hens will be fed a ration with a different chemical additive and the cholesterol content of their eggs will be measured.

1. What is the explanatory variable, and is it quantitative or categorical?

A. number of laying hens in each group which is categorical
B. cholesterol content of the hens’ eggs which is categorical
C. cholesterol content of the hens’ eggs which is quantitative
D. number of laying hens in each group which is quantitative
E. type of chemical additive to the group of hens’ feed which is categorical
F. type of chemical additive to the group of hens’ feed which is quantitative
G. breed of chicken which is categorical
H. breed of chicken which is quantitative

Answer 1

E. type of chemical additive to the group of hens’ feed which is categorical

Explanation:

Explanatory variable is the variable which explains the target variable of the study. In this example cholesterol content of the eggs yolks is the main focus of the study.

Categorical Variable is a variable which can assume discrete and limited number of values.

The study observes the changes in cholesterol levels of the egg yolks by feeding groups of laying hens with different chemical additive. Therefore type of chemical additive to the group of hens’ feed is the explanatory variable.

Since the types of chemical additive are limited and discrete, it is categorical.