A researcher is interested in determining whether a new "anti-anxiety" drug relieves anxiety in college students studying statistics. Fifteen students were assigned to one of three conditions: five students received a placebo, five received 50 mg of the new drug, and five received 100 mg of the drug. The students were then placed in a quiet room and were given 15 statistics problems to do. They were administered by the researcher's assistant. After completing the problems, the papers were scored and the number of errors made by each student was used to determine their levels of anxiety.
Based on the information provided above:
a. Identify the dependent and independent variables.
b. Determine the type of measurement scale used (interval, ratio, and ordinal, nominal).
c. Explain why the sample used is or is not representative of the population.
d. Using only the information above, give an operational definition of anxiety.
e. Define confounding variable and cite some examples that could create problems in this experiment.