Day 51 – Review on Mean, Median & Mode

In your math class you and your friends have the following grades. John 58 64 55 54 59 85 80 Sejah 90 89 92 93 95 Jack 78 68 73 42 Lucy 97 72 98 Jorge 67 84 96 Your teachers announced that to calculate grades, mean will no longer be used. The new measure will be the median. Who does this help? Who does this hurt? Why? (Please organize your findings so that I can understand the results.)

Answer Mean Median John 64.125 58.5 Sejah 90.375 90 Same Jack 72.875   Mean Median John 64.125 58.5 Sejah 90.375 90 Same Jack 72.875 75.5 Lucy 88.75 94 Jorge 80.625 81

Example 1 On his first 5 biology tests, Bob received the following scores:  72, 86, 92, 63, and 77.  What test score must Bob earn on his sixth test so that his average (mean score) for all six tests will be 80?  Show how you arrived at your answer.

Bob must get a 90 on the sixth test Solution Set up an equation to represent the situation.  Remember to use all 6 test scores: Bob must get a 90 on the sixth test

Example 2 The mean (average) weight of three dogs is 38 pounds. One of the dogs, Sparky, weighs 46 pounds. The other two dogs, Eddie and Sandy, have the same weight. Find Eddie's weight. Let x = Eddie's weight Let x = Sandy's weight (they weigh the same, so they are both represented by “x”.)

Average: sum of the data divided by the number of data. Cross multiply and solve

In your math class you and your friends have the following grades In your math class you and your friends have the following grades. Your teachers announced that to calculate grades, mean will no longer be used. The new measure will be the median. Who does this help? Who does this hurt? Why? (Please organize your findings so that I can understand the results.) John 58 64 55 54 59 85 80 Sejah 90 89 92 93 95 Jack 78 68 73 42 Lucy 97 72 98 Jorge 67 84 96

Answer MEAN MEDIAN John 64.12 58.5 Mean Sejah 90.37 90 Same Jack 72.87 75.5 Median Lucy 88.75 94 Jorge 80.62 81