how to solve b)?

Data collected on the yearly registrations for a Six Sigma seminar at the Quality College are shown in the following table: This exercise contains only parts a and b. a) Using a 3-year moving average, the forecasted registrations (in thousands) for years 4 through 12 are (round youn responses to one decimal place): b) Using a 3-year weighted moving average in which the registrations in the most recent year are given a weight of 2, and registrations in the other 2 years are each given a weight of 1 , the forecasted registrations (in thousands) for years 4 through 12 are (round your responses to one decimal place)