Problem 3: Nerves and Conversation

Dr Johnson is interested in testing the hypothesis that people talk more when they are nervous. She obtains 36 volunteers from undergraduate classes to participate in her experiment.She randomly assigned them to one of two conditions and scheduled a separate appointment time with each student.When a student in Group 1(Low Stress) arrives for their appointment they are told that in 10 minutes they will be asked to describe how friendly they are by completing a true-false personality measure.Students in Group 2 (High Stress) were told that in 10 minutes they will be asked a set of questions by a panel of clinical psychologists (measurement specialists) to determine how friendly they are.In both groups the conversations between the waiting student and the experimenter were recorded for 10 minutes.During this waiting time, the experimenter made certain set comments if no conversation occurs during a one-minute interval, and consistently answered questions with brief responses such as yes or no.The percent of time that the student talked during the 10 minute period was recorded. Assume that the high stress group is more nervous than the low stress group. The numbers below reflect the percent of time that students talked during the 10-minute period.Run the proper t-test to test whether people talked more when they were nervous.

Low Stress:.26.32.29.38.37.41 .39.40.22.28.24.40.31.38.39.30.32 .44

High Stress:.36.39.46.39.44.45.38.45.45.43.37.48.40.48.42.33.39 .42

Statistical Hypotheses: H₀:____________________H₁:______________________

State Hypotheses in words.

H₀: ______________________________________________________________________

H₁: ______________________________________________________________________

Proper t-test:____Independent Sample t-test____One-tailed or two-tailed? _____________

Run the analysis using JASP and print the t-test output.Include a boxplot of both high and low stress groups. Using APA , state your conclusion based on the research hypothesis and the statistical results obtained.

In addition, calculate r ² and explain what it means in terms of the effect size in this example.

Treatment effect size