An electrical contractor's records during the last five weeks indicate the number of job request: Week: 1 2 3 4 5 Request: 20 22 18 21 22 Predict the number of requests for week 6 using each of these methods: (a) Naive (b) a four-period moving average (c) weighted moving average using 0.50 for week 5, 0.30 for week 4, and 0.20 fr week 3 (d) Exponential smoothing with a smoothing constant ?=.30. Use 20 for week 2 forecast.