#1 How many observations should a time study analyst plan for in an operation that has a standard deviation of .1 minutes per piece if the goal is to estimate the mean time per piece to within .1 minute with a confidence of 95.5 percent?

Number of observations:

#2

A manager uses a trend equation plus quarterly relatives to predict demand. Quarter relatives are SR₁ = 0.9, SR₂ = 0.95, SR₃ = 1.05, and SR₄ = 1.1_. The trend equation is: Ft = 12 + 3t. Over the past nine quarters, demand has been as follows:

Period, t:	1	2	3	4	5	6	7	8	9
Demand:	14	20	22	24	26	28	30	36	42

Compute the MAD and tracking signal for each period. (Negative values should be indicated by a minus sign. Round your intermediate calculations and final answers to 3 decimal places.)

Period, t	Demand	MAD	Tracking signal
1	14
2	20
3	22
4	24
5	26
6	28
7	30
8	36
9	42