Final answer:
The calculation for a weighted moving average forecast requires specific weights and actual data from previous weeks, which are not provided in the information. Thus, it is not possible to give a forecast for the 4th week without this data.
Step-by-step explanation:
To calculate the weighted moving average forecast for the 4th week, we need the weights and actual data for the previous weeks. However, the given information does not provide the necessary weekly weights or data to perform this calculation. If the data and weights were provided, the forecast for the 4th week would be the sum of each previous week's data point multiplied by its respective weight, divided by the sum of the weights.
For example, if we have weights as follows:
- Weight for Week 1: w1
- Weight for Week 2: w2
- Weight for Week 3: w3
And actual data for the weights given above:
- Week 1 data: d1
- Week 2 data: d2
- Week 3 data: d3
Then the weighted moving average for week 4 would be calculated as:
(w1×d1 + w2×d2 + w3×d3) / (w1 + w2 + w3).
Without specific weights and data, it is not possible to provide the weighted moving average forecast for the 4th week.