Data
6 Mean: The Average Mean is the average number in your data. Let’s say that these are the numbers in your data: 1 2 3 4 5 6 7 8 9 10 Next, divide the sum by the number of numbers in the data set. 2, 6, 14, 2, 5, 8, 9, 4, 7, 3 To calculate the mean, first add up all of the numbers. 2 6 14 5 8 9 4 7 3 There are ten numbers in the set. So, 60 ÷ 10 = 6 + The mean of your data set is 6. 60
Median: The Middle Number In order to find the median of a data set, you must rewrite the numbers in numerical order. Let’s use the same data set. 2, 6, 14, 2, 5, 8, 9, 4, 7, 3 Rewrite the set into numerical order. 2, 2, 3, 4, 5, 6, 7, 8, 9, 14 Wait, there looks like there’s a problem. There is an even number of data so there are two numbers left in the middle. If this happens find the average of those two numbers, that is the median. Cross out one number at a time alternating the left side then the right side. The number that can’t be crossed out is the median. 5 + 6 The median is 5.5! 11 ÷ 2 = 5.5 11
Mode: The Number that Appears Most Often This one is simple. Look at your list of data What number appears most in the data? 2, 6, 14, 2, 5, 8, 9, 4, 7, 3 2 appears twice and that is more than any of the other numbers. So the mode of your data set is 2.
Range: The Domain of Data 2, 6, 14, 2, 5, 8, 9, 4, 7, 3 In order to find the range, subtract the minimum value of data from the maximum value. 14 2 In our data, the minimum is 2 and the maximum is 14. 12 The range of the data is 12!
The Line Graph One way to view the data you’ve collected is in a line graph. 2, 6, 14, 2, 5, 8, 9, 4, 7, 3 X X X X X X X X X X 0 2 4 6 8 10 12 14 16 Place an X on the line for each number in your data set. The line graph is helpful for visualizing the mean, median, and mode.