14   5 Based on an earlier study, Sinead decided to investigate the extent to which people are influenced by other people’s laughter. Participants were asked to rate the ‘funniness’ of a set of 10 jokes. The 10 jokes were videoed being told by a professional comedian. Random samples of participants were then shown the video and asked to rate the funniness of each joke on a scale of 1 (unfunny) to 7 (extremely funny). A first sample of participants watched the video with no laughter track added. A second sample watched it with a backing track of fake machine-generated laughter. A third sample watched it with a backing track of real laughter generated by an audience. The funniness ratings for each joke were then averaged for each of the three samples. The mean ratings obtained are given in Figure 4. No laughter Fake laughter Real laughter Joke 1 2.3 1.9 1.0 2 3.2 2.9 4.2 3 2.1 4.2 3.8 4 3.4 1.9 3.8 5 2.5 3.5 3.8 6 2.2 3.0 3.7 7 1.3 1.9 2.5 8 1.3 2.4 2.9 9 1.4 3.5 4.3 10 2.5 4.0 5.0 Figure 4 Sinead’s belief is that jokes are perceived to be more funny if accompanied by the sound of laughter. The test values calculated using the data in Figure 4 are t = 1.93 for ‘Fake laughter’ compared to ‘No laughter’ and t = 3.51 for ‘Real laughter’ compared to ‘No laughter’ Turn over 15   Question 5 continued (a) State the hypotheses being tested and decide whether these data support Sinead’s belief. (4) _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ (b) Conduct a t-test using data from Figure 4 to investigate whether there is evidence of any difference between ‘Fake laughter’ and ‘Real laughter’ in terms of the perceived funniness of jokes. (8) _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________