00:00Please see the link in the description to download a worksheet for this video.
00:05We use the word average at home and in our jobs. You may have heard the word
00:10average when people were talking about sports. For example, the team with the red shirts scores
00:15an average of 3 goals per game. You may have heard the word average when people are talking
00:20about the weather. For example, the average high temperature during June in Minneapolis
00:25is 79 degrees Fahrenheit. You may have heard people use the word average when they're talking about
00:31speed. For example, the average speed for these boats is 15 miles per hour. In this video, we'll
00:38learn the formula to calculate the average for a set of numbers, other ways to write the formula
00:44to calculate the average, and other words and phrases related to average. Let's start with
00:49the formula to calculate the average for a set of numbers. In math, the word average is the
00:55solution to this division problem. This formula tells us how to calculate the average for a set
01:01of numbers. The average of that set equals the sum of those numbers divided by the number count.
01:07Here's an example. Let's say we want to know the average weight of these dogs. The one with the red
01:12leash weighs 12 pounds, the one with the blue leash weighs 7 pounds, and the one with the yellow leash
01:19weighs 8 pounds. To calculate the average, we start by writing the formula. Then, we write down the
01:26numbers in this set. Then, we find the number count. There are 3 numbers in this set. So, the number count
01:33is 3. Next, we calculate the sum of the numbers. 12 plus 7 plus 8 equals 27. The sum of the numbers in
01:42this set is 27. Now, we use substitution to replace the words in the formula with numbers. We replace
01:50the phrase sum of numbers with 27. We replace the phrase number count with the number 3. Finally,
01:58we do the division problem. 27 divided by 3 equals 9. The average weight of these dogs is 9 pounds.
02:06Please note that none of the dogs weighs 9 pounds. We calculate the average for a set of numbers.
02:12We do not select one of the numbers in the set when trying to determine the average. Next, we'll show
02:18other ways to write the formula to calculate the average. We often write the formula for average,
02:24like this. That's because this horizontal bar means the same as the division symbol. Both of these formulas
02:31are saying the same thing. Our last topic is to discuss other words and phrases related to average.
02:37In everyday use, we use the word average, but on a math test or in math books, you might come across
02:44the word mean. Some people even use the phrase arithmetic mean. The word average and the word
02:50mean can be used interchangeably, so they have the same formula. Sometimes you'll see formulas use the
02:58word value rather than the word number. Other times, you will see the phrase how many numbers there are
03:04instead of the phrase number count. All of these are describing the same idea.
03:09Thanks for your attention.
