Chapter 10.2, Problem 27PB

Body language In an experiment investigating body language (M. Koppensteiner et al., Personality and Individual Differences, vol. 74, 2015, pp. 182–185), researchers turned short video clips of randomly selected speeches by male and female politicians into an animated, gender-neutral stickfigure clip. These clips showed the movements of the upper body parts during the speech. Each clip was rated (on a scale from −100 to 100) by a random sample of students in terms of personality traits. For one trait measuring the perceived dominance of a speaker, the following statistics on the scores were reported (a higher score means higher dominance):

1. a. Set up the hypotheses for a significance test to analyze whether the population mean score differs between clips based on a male or female speaker.
2. b. Using software in which you can use summary statistics (or access the data set at the book’s website), find the P-value for the significance test. Interpret it and report the conclusion for a significance level of 0.05.
3. c. If you were to construct a 95% confidence interval for the difference in population means, would it contain 0? Answer based on the result of part b, without actually finding the interval.