Final answer:
To calculate the 13th period forecast using a three-period moving average, add up the values from periods 10, 11, and 12, divide by three, and round the result to two decimal places. The precise forecast cannot be given without the actual data for those periods.
Step-by-step explanation:
To forecast the 13th period based on a three-period moving average, you would need the data for the 10th, 11th, and 12th periods. The forecast would be the average of those three periods. As the exact values for these periods have not been provided in the question, a general explanation can be given. To calculate a three-period moving average, you add up the values for the three periods and divide by three. Finally, you round the result to two decimal places, as per the given instruction in the question.
If we had the total of the 10th, 11th, and 12th periods as 921.996 (as an example), the forecast for the 13th period would be this total divided by 3. According to the rules of significant figures provided, the answer should be rounded to the hundredths position. Hence, we would round 921.996 to 922.00 since the digit in the thousandths place is greater than 5.