Chen Integrated Systems recently received a large shipment of LKP fusion units from Anderson Industries and a large shipment of similar units from Burnett Technology. You randomly select 12 of the Anderson units and 12 of the Burnett units. The Anderson sample averaged 1092 hours of useful life, with standard deviation of 29.2 hours. The sample of Burnett units averaged 984 hours, with standard deviation of 31.4 hours. Using a 90% confidence level, construct and interpret an appropriate interval estimate of the difference in average life for the two populations represented. Assume that the distribution of useful life in the two populations represented is normal and that the two population distributions have equal standard deviations.