A dishwasher technician knows that the mean setup time to unpack, assemble, and fine tune a dishwasher is 5.8 hours with a standard deviation of 0.896 hours. the times for the three steps are independent. the mean and the standard deviation for unpacking are 1.6 hours and 0.3 hours, and for the assembly time are 2.8 hours and 0.78 hours, respectively. what are the mean and standard deviation times for fine tuning?
a. μ = 1.3 hr sd = 0.323 hr
b. μ = 1.4 hr sd = 0.323 hr
c. μ = 1.4 hr sd = 0.562 hr
d. μ = 2.2 hr sd 1.14 hr
e. μ = 1.3 hr sd = 0.15 hr