A rental car manager estimates the number of full-size sedans rented per week so that she can maintain adequate number of cars in the lot. Data for the past 10 weeks are shown here:

Week Rentals Week Rentals
1 23 6 28
2 24 7 32
3 32 8 35
4 26 9 26
5 31 10 24
a) Prepare a forecast for week 11 by using a five -week moving average
b) Prepare a forecast for week 11 by using a 3-period weighted moving average, giving the weight of 0.5 to the most recent week, 0.3 to the second week and 0.2 to the third week.
c) Prepare a forecast using exponential smoothing method with α = 0.2. Forecast for week 1 was 22.