VIEWS: 0 PAGES: 9 POSTED ON: 7/2/2013 Public Domain
Mean, Median and Mode, and Range Module 1, Lesson 4 Online Algebra 1 VHS@pwcs Cami Craig Numbers Everywhere Numbers are a great way to recognize trends and interpret data. One way to interpret is to use measures of central tendency. These are mean, median, mode and range. Mean The mean is one of the most common statistics that we look at. You might know mean as the average. To find the mean: o Add up all of the data o Divide by the number of items of data. To find the mean of the numbers in the box above. o Add up all the data 0 + 1 + 2 + 3 + 5 + 7 = 18 o Divide by the number of items of data: 18/6 = 3. o The mean or average is 3. Median The median is a number that is the middle when the numbers are in order. How we find this is different if we have an even or odd number of items in are data set. For an odd number of items. For an even number of items: • Put the numbers in numerical order. • Put the numbers in numerical order. • Find the number in the middle, there will be • There will be 2 numbers in the middle. Find exactly one. the sum of the 2 middle numbers and divide by 2. In the set of numbers: In the set of numbers: 1, 1, 2, 2, 4, 5, 8, 11 2, 3, 5, 5, 6, 8, 9, 9 12, 13, 14 2 and 4 are in the middle. Notice that there are 3 There are 11 numbers, so our 6th number will numbers on each side of the 2 and 4. be the median. Notice that there are exactly 5 numbers on either side of 8, or 6th number. The 2 + 4 = 6, and 6/2 = 3, so 3 is the median. Mode The mode is the number that occurs the most. In the set of numbers. In the set of numbers: 8, 9, 2, 5, 6, 6, 2, 9, 9,6, 6 0, 1, 2, 4, 5, 7, 9, 3, 12 There are four 6’s therefore 6 There are no numbers that repeat. is the mode. Therefore there is no mode. In the set of numbers: 2, 2, 3, 3, 4, 5, 6 There are two 2’s and two 3’s. In this case we have more than 1 mode. The mode is both 2 and 3. (a double mode) Range o The range is the difference between the greatest and the least values of a set of data. o Example: {6,3,10,14,2, 22,11}. The greatest value is 22 and the least is 2. The range is 22 – 2 which is 20. o Example: {-10, 15, -32, 45, 23,20}. The greatest value is 45 and the least is -32. The range is 77. (45 - -32) Try it! Find the mean, median, mode, and range of each set of numbers. {23, 15, 17, 19, 23, 16, 34} {0, 20, 25, 42, 12, 25, 18, 22, 16, 32} Mean: 21 Mean: 21.2 Median: 19 Median: 21 Mode: 23 Mode: 25 Range: 19 Range: 42 Mean, Median, Mode & Range Remember: o The mean is the average of a set of numbers. To find it add up the numbers and divide by the number of items in the data set. o The median is the number in the middle when the numbers are in numerical order. If there is an even number, you need to find the sum of the 2 middle numbers and divide by 2. o The mode is the number that occurs the most. There can be one mode, no mode or more than one mode. o The range is the difference between the greatest and the least values in a set of data. On your own Homework is Worksheet 1.4