The time required by a specialized workforce to assemble 100 units of the same type of transistorized assembly was measured. The average time was 10.2 minutes with a standard deviation of 1.8 minutes. What is the lower limit of the confidence interval for the actual average time for assembly at the 99% confidence level? a) 9.94 b) 9.90 c) 9.97 d) 9,85 e) 9.74