Scenario:
One well-known psychological experiment measures reaction time (RT) to a stimulus in microseconds (msec). In one version, intended to simulate the effects of texting while driving, participants in an experimental group (EG) are directed to attend to a visual display of words and quickly press a button when a loud noise is heard. A control group (CG) is directed to ignore the visual display and quickly press the button when the noise is heard. Assume the researcher is using an alpha value of .05 in analyzing the results of the experiment, and that she is interested in whether the RT of the experimental group is greater than the RT of the control group. Also assume that RT scores generally tend to be normally distributed, and that the researcher has a sample of at least 30 participants in each group to compare, but that the population parameters are not known.
Answer the following regarding the scenario:
- State the null and alternative hypotheses, both in words and in symbols.
- Under the conditions described in the scenario, what statistical test would be appropriate? Explain the rationale for your answer.
- Would it be most appropriate to use a two-tailed test, a left-tailed test, or a right-tailed test? Why?
- In one paragraph, describe the conclusion you would reach about the participants' performance if the P-value of the hypothesis test was determined to be .065. Include the rationale for your conclusion.