Please help me to understand this problem:

The concentration of active ingredient in a liquid laundry detergent is thought to be affected by the type of catalyst used in the process. 111e standard deviation of active concentration is known to be 3 grams per liter, regardless of the catalyst type. Ten observations on concentration are taken wi'l each catalyst, and the data follow: Catalyst 1: 52.5, 66.5, 55.4, 55.4, 55.2, 62.5, 5?.5, 53.2, 57.2, 21.0 Catalyst 2: 55.0, 71.9, ms, 59.3, 54.5, 69.5, 53.5, 59.4, 55.3, 55.5 (a) Find a 95% twosided condence interval on the difference in mean active concentralions for the two catalysts. l:l 5 \"1 _ \"2 5 l:l. Round your answer to two decimal places (e.g. 98.?5). (b) Is 1ere any evidence to indicate diet the mean acve concentrations depend on the choice of catalyst