1. a. What is categorical data. Why do we need different types of tests for categorical data? 1.b. The production manager at a Walton factory suspects that the night-shift workers use more hours of sick leave than the day-shift workers. The workers at this factory are rotated between shifts. Each worker works the day-shift for two months, then works the night shift for two months and so on. The manger at the factory selected 12 workers randomly and recorded the total number of hours of sick leave each of these workers used during the two months of dayshift and then during the two months of night shift. The results are given in the following table.

Day	22	32	15	24	15	0	28	10	10	38	16	12
Night	16	60	0	30	36	24	40	30	30	24	30	20

On the basis of the above data, can we conclude that median number of sick leave hours used by workers is higher for night-shift workers? Use .025 level of significance.