Chapter B.6, Problem 18AYU

Reaction Time In an online psychology experiment sponsored by the University of Mississippi, researchers asked study participants to respond to various stimuli. Participants were randomly assigned to one of three groups: Group 1, the simple group, required to respond as quickly as possible after a stimulus was presented; Group 2, the go/no-go group, required to respond to a particular stimulus while disregarding other stimuli; and Group 3, the choice group, required to respond differently depending on the type of whistle sound, the subject must press a certain button. The researcher wants to determine if the mean reaction times for each stimulus are equal. The reaction time (in seconds) for each stimulus is presented in the table.

Simple	Go/No-Go	Choice
0.430	0.588	0.561
0.498	0.375	0.498
0.480	0.409	0.519
0.376	0.613	0.538
0.402	0.481	0.464
0.329	0.355	0.625

Source: PsychExperiments; The University of Mississippi; www.olemiss.edu/psychexps/

1. (a) What type of experimental design is this?
2. (b) What is the response variable? What is the explanatory variable? How many levels of treatment are there in this experiment?
3. (c) State the null and alternative hypotheses.
4. (d) Verify that the requirements to use the one-way ANOVA procedure are satisfied. Normal probability plots indicate that the sample data come from a normal population.
5. (e) Test the hypothesis that the mean reaction times for the three stimuli are the same at the α = 0.05 level of significance.
6. (f) Draw boxplots of the three stimuli to support the analytic results obtained in part (c).