Revisit the problem ?rst presented in Example regarding a company's attempt to improve its safety performance. Speci?cally, we recall that to improve its safety record, the company began tracking the time in between recordable safety incidents. During the ?rst year of the pro- gram, the waiting time (in days) until the occurrence of a recordable safety incident was obtained as
S1 = {16, 1, 9, 34, 63, 44, 1, 63, 41, 29}
The data record for the second year of the program is
S2 = {35, 26, 16, 23, 54, 13, 100, 1, 30, 31}
On the basis of this data, which shows a mean time to incident as 30.1 days for the ?rst year and 32.9 days for the second year, the company's safety coordinator is preparing to make the argument to upper management that there has been a noticeable improvement in the company's safety record from Year 1 to Year 2. Is there evidence to support this claim?