Using johnson's rule for 2-machine scheduling, the sequence is: six jobs are to be processed through a two-step operation. the first operation involves sanding, and the second involves painting. processing times are as follows scheduled order job operation 1 (hours) 12 operation 2 (hours) job 10 for the schedule developed using johnson's rule, the total length of time taken to complete the six jobs (including the 2nd operation)- 51 hours (enter your response as a whole number).

Arandom sample of 15 observations is used to estimate the population mean. the sample mean and the standard deviation are calculated as 172 and 63, respectively. assume that the population is normally distributed. a. with 99 confidence, what is the margin of error for the estimation of the population mean? b. construct the 99% confidence interval for the population mean. c. construct the 95% confidence interval for the population mean. d. construct the 83% confidence interval for the population mean. hint: you need to use excel function =t. inv.2t to find the value of t for the interval calculation.