Final answer:
The margin of error in the report on the average amount of time a 10-year-old American child spends playing outdoors per day is 2.57 minutes.
Step-by-step explanation:
The report states that the average amount of time a 10-year-old American child spends playing outdoors per day is between 20.58 and 25.72 minutes.
To calculate the margin of error for this report, you would take the upper limit and subtract the lower limit of the average time range, and then divide by 2. In this case, the margin of error is (25.72 minutes - 20.58 minutes) / 2, which equals 2.57 minutes.