Question

one-hundred random chosen lamps lifetime are measured. mean = 1320, SD=180 (units = hours).

a. If "A" represents sample mean of the lifetime of one-hundred lamps measured in given units, what is the expected value of "A" and the SD of "A"?

b. if units were instead = days and not hrs, how would answer for question "a." change (both mean and SD)?

c. what is probabiltiy that sample mean is b/w one-thousand-three-hundred and one-thousand-three-hundred-fifty hrs...using central limit theorem?

d,if life-time of lamps are normally distributed, probabiltiy that randomly chosen lamp has life-time b/w one-thousand-three-hundred and one-thousand-three-hundred-fifty hrs?

Answer 1