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 stick figure 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):

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.
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.
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.

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Clips based on male speaker female speaker Mean SD 10.7 30 30 26.3 27.8 -1.1