# How many conditions need to be counterbalanced

## How many conditions need to be counterbalanced

Question #3: Develop and state your own research hypothesis and its corresponding two statistical hypotheses [i.e., the alternative hypothesis (H1) and the null hypothesis (H0)]. Describe the relationships between the two statistical hypotheses; the relationship between the alternative hypothesis and the research hypothesis; and state the two possible results after hypothesis testing. How do Type I and Type II errors relate the alternative and null hypotheses?

Question #4: Ivan adopted a 3 x 4 mixed factorial design to study the effects of A and B on a dependent variable. Factor A (IV #1) is a between-subjects variable. Factor B (IV #2) is a within- subjects (repeated) variable. In order to control for possible order effects, Ivan decided to use complete counterbalancing. Please answer the following questions and justify your answer.

(a) How many groups of participants are required in Ivan’s experiment?
(b) How many conditions need to be counterbalanced?
(c) How many sequences need to be enumerated? Why?
(d) If Ivan wanted to include five participants for each sequence, then, how many participants are

required in his experiment?

Question #5: Educational psychologists were interested in the impact the “Just Say No!” Programand contracts on drunk driving among teens. This program was a pilot program. The investigators identified gender as a participant characteristic highly related to alcohol use among teens that would require a matching strategy and analysis statistically. With the cooperation of school officials, 16- year-old students were matched and randomly assigned with equal numbers of males and females in each group. Group A participated in a “Just Say No!” program, which required a one-hour information session instead of P.E. for six weeks. Students were presented with written factual information, motivational lectures, guidance films, and assertiveness training. Students were also encouraged to sign a personal responsibility contract that stipulated that they would not drink and drive. Group B participated in regular P. E. classes for the six-week experimental period. A two- factor factorial analysis was used to analyze the data. Please answer the following questions and justify your answer.

(a) Identify the experimental design.
(b) What is the independent variable? What is the dependent variable?
(c) Diagram this experimental design.
(d) What are the potential confounds?
(e) How many main effects, interaction effects, simple main effects of A, and simple main effects

of B are there?