The height of your workstation desk is one of the essential criteria for creating the perfect ergonomic workspace, whether at home or in your office. A company's plant manager is currently considering two designs of ergonomic computer desks for their employees. An experiment is performed to help with the purchasing decision. 43 randomly selected employees used the design A computer desk for a week. They used the design B computer desk for the following week. On a 15point scale, their comfort level was recorded in the EXCEL file Co_mputerDesk.xlsx. Use EXCEL and an appropriate hypothesis test to help the plant manager to answer the following research question. Research Question: Are the comfort levels of the two designs (design A and design B) different? CO Figure 1: Design A Histogram Figure 2: Design B Histogram CO Frequency Frequency 5 6 8 6 7 8 9 10 Comfort Level Ratings Figure 3: Histogram of Differences (A-B) Comfort Level Ratings Figure 4: Boxplots of Comfort Level ratings 6 8 10 12 14 CO Frequency Comfort Level Ratings 4 O -6 -4 -2 0 Design A Design B2. (1 mark) Which graphical display would be useful to check normality assumption for this hypothesis? A V . Figure 1 . Figure 2 . Figure 3 . Figure 4 . Figure 1 8L 2 . Figure 3 8L 4 'I'II'I'IUF'IUJ} . No need to check normality assumption In") .All four figures are needed 3. (1 mark) How can you check the assumption of equal variances? 0 . Comparative boxplots could be used (e.g. if the sizes of boxes are similar or not) . Descriptive statistics such as variance, standard deviation and range could be used . Descriptive statistics such as mean and median could be used . The histogram of differences could be used Both A 8: B could be used mmUnm} . No need to check the assumption of equal variances For the remaining questions you may assume that any relevant assumptions have been met. 4. [2 marks) The absolute value of the test statistic is equal to (3dp) 5. {1 mark) The degrees of freedom is equal to (Integer) 6. {1 mark) The pvalue is larger than 0.05 3 7. [2 marks) The test shows that the comfort level ratings were A. significantly different between design A and design B, possibly greater for design A. B. signicantly different between design A and design B, possibly greater for design B. C. not significantly different between the two design of the computer desks. 0