To calculate a 3-month moving average forecast for October, you need to average the values from the previous three months (July, August, and September).

Here are the values for those months:

• July: 12
• August: 5
• September: 7

The 3-month moving average forecast for October is calculated as:

$\text{Forecast for October} = \frac{12 + 5 + 7}{3} = \frac{24}{3} = 8$

So, the correct answer is:

2) 8

Would you like more details or have any other questions? Here are 5 related questions you might find interesting:

1. How does the length of the moving average window affect the forecast?
2. What are the limitations of using a simple moving average for forecasting?
3. How would you compute a weighted moving average, and why might it be preferred?
4. How would you adjust the moving average calculation if the data has seasonality?
5. What is the difference between a simple moving average and an exponential moving average?

Tip: Moving averages smooth out short-term fluctuations and highlight longer-term trends or cycles. Choosing the right window length is crucial for balancing responsiveness with smoothness.