the production rate trend

1. A selected Forecast Model showed the lowest MAD at the beginning of the year with $60.5. If the following three quarters reflected the following MAD:

  Q2: $60.2 Q3: $75.4 Q4: $78.9
Would you stay using this model for the next year? Explain your answer.

2. The EOQ of the product you are purchasing is 20,350units. The supplier runs 40,000units per lot. He wants you to buy all of them since you are the only buyer of this product. What will you do and explain?

3. A six sigma project was done and it was found that the temperature was affecting the production rate. The initial project measured the production rate trend to identify the potential reasons of concern. If you has to decide which parameter you need to control,(Temperature or the production rate), explain which one and why?