Chapter 17 formulas

Question 1

what is the formula when using a smoothing constant

Answer 1

ie smoothing constant 0.2

TSvalue x 0.2 + Forecast value x (1-.2) gives the next week’s forecast value

Question 2

What are the calculations for forecast

Answer 2

wk / Ts value/ forecast / forecast error / absolute/ squared/ % error / absolute % error

Question 3

Deasonalized: what is the formula for moving average

Answer 3

add the first quarter values / 4

then the last 3 plus 1 from the next etc

Question 4

Deasonalized: what is the formula for centred moving average

Answer 4

take the ist moving average + next moving avg / 2

then for the next one, we take 2nd moving avg + 3rd moving avg / 2 etc

Question 5

Deasonalized: How do you calculate seasonal irregular component

Answer 5

TS value / Centered moving average

Question 6

Deasonalized: How do you calculate teh seasonal index

Answer 6

take all of the seasonal irregular values for each quarter and add each quarter up / # (to find the average)

Question 7

Deasonalized: how do you calculate the Adjusted seasonal index

Answer 7

Seasonal index x # of seasonal / sum of unadjusted seasonal index

next, take the seasonal index x the number you just calculated

Ie. sum of all seasonal index = 4.036

Adjusted:

Question 8

Deasonalized: how do you calculate the deseasonalized sales

Answer 8

sales/ seasonal index or

sales / adjusted seasonal index

Question 9

Deasonalized: how do you calculate the deseasonalized sales

Answer 9

sales/ seasonal index or

sales / adjusted seasonal index

Question 10

What is also required in order to calculate the next period for deseasonalized sales

Answer 10

a regression equation

T13 = b0 + b1t
- t in this case would equal 13