Question

“Condition” is the independent variable in the experiment where participants were exposed to a traumatic film. The levels (four groups) for the IV are:

1. No-task control;

2. Reactivation only;

3. Reactivation + Visuospatial task (i.e., playing Tetris); and

4. Visuospatial task (Tetris) only.Participants were randomly assigned to one of the four conditions. Their number of intrusive memories over the next week was recorded (dependent variable).

A. State the null and alternative hypotheses for this one-way ANOVA analysis.

Null hypothesis using symbol:

Alternative hypothesis using symbol (according to the researchers’ hypothesis):

Null hypothesis in words:

Alternative hypothesis in words (paraphrase the researchers’ hypothesis):

Answer 1

Using symbol:

Using words:

Null hypothesis: There is no difference in the mean number of intrusive memories among four traumatic film conditions.

Alternative hypothesis: At least one mean number of intrusive memories among four traumatic film conditions is different.

Explanation: The one way ANOVA analysis test whether the mean value among each independent variable is the same or at least one group mean differ significantly.