= 0.28 or 28%Now apply this percent to the entire population of the league. Since 28% of the polled players wanted to
play in the rain, 28% of all players should want to play in the rain.
× 750 = 210
The only range that contains this value is (D), so that is the correct answer. To actually calculate the
margin of error, add and subtract 4% to the actual percent of 28% to get a range of 24–32% of the total.
24% of 750 = 18032% of 750 = 240Therefore, the entire range is 180 to 240.
AVERAGES
What Is an Average?
The average (also called the arithmetic mean) of a set of n numbers is simply the sum of all the numbers
divided by n. In other words, if you want to find the average of three numbers, add them up and divide by
- For example, the average of 3, 7, and 8 is , which equals , or 6.
That was an easy example, but average questions on the SAT won’t always have clear solutions. That is,
you won’t always be given the information for averages in a way that is easy to work with. For that
reason, we have a visual aid, like the Ratio Box for ratios, that helps you organize the information on
average questions and find the answer.
We call it the Average Pie. Here’s what it looks like:
The total is the sum of all the numbers you’re averaging, and the number of things is the number of