Production Forecast
1. **State the problem:** We need to forecast this week's production for Monday to Friday using two methods: (i) 4-week simple moving averages and (ii) weighted moving averages with weights 0.50, 0.20, 0.10.
2. **Given data table:**
| Week | Monday | Tuesday | Wednesday | Thursday | Friday |
|--------------|--------|---------|-----------|----------|--------|
| 4 Weeks Before | 320 | 290 | 310 | 260 | 330 |
| 3 Weeks Before | 340 | 300 | 320 | 280 | 350 |
| 2 Weeks Before | 350 | 310 | 330 | 270 | 340 |
| Last Week | 360 | 320 | 340 | 290 | 360 |
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### (i) 4-week Simple Moving Averages (SMA)
3. SMA is the average of the last 4 weeks for each day.
Calculate for Monday:
$$\frac{320 + 340 + 350 + 360}{4} = \frac{1370}{4} = 342.5$$
For Tuesday:
$$\frac{290 + 300 + 310 + 320}{4} = \frac{1220}{4} = 305$$
For Wednesday:
$$\frac{310 + 320 + 330 + 340}{4} = \frac{1300}{4} = 325$$
For Thursday:
$$\frac{260 + 280 + 270 + 290}{4} = \frac{1100}{4} = 275$$
For Friday:
$$\frac{330 + 350 + 340 + 360}{4} = \frac{1380}{4} = 345$$
---
### (ii) Weighted Moving Average (WMA) with weights 0.50 (latest week), 0.20, 0.10 (three weeks before)
4. Weights are given as 0.50 for last week, 0.20 for 2 weeks before, 0.10 for 3 weeks before. Since four weeks total are given, we assume the first week's weight is 0.
Calculate for Monday:
$$0.50 \times 360 + 0.20 \times 350 + 0.10 \times 340 = 180 + 70 + 34 = 284$$
For Tuesday:
$$0.50 \times 320 + 0.20 \times 310 + 0.10 \times 300 = 160 + 62 + 30 = 252$$
For Wednesday:
$$0.50 \times 340 + 0.20 \times 330 + 0.10 \times 320 = 170 + 66 + 32 = 268$$
For Thursday:
$$0.50 \times 290 + 0.20 \times 270 + 0.10 \times 280 = 145 + 54 + 28 = 227$$
For Friday:
$$0.50 \times 360 + 0.20 \times 340 + 0.10 \times 350 = 180 + 68 + 35 = 283$$
---
**Final forecast:**
| Day | SMA Forecast | WMA Forecast |
|-----------|--------------|--------------|
| Monday | 342.5 | 284 |
| Tuesday | 305 | 252 |
| Wednesday | 325 | 268 |
| Thursday | 275 | 227 |
| Friday | 345 | 283 |