Comparing the mean, median, mode and range Six groups of students - P, Q, R, S, T and U – all sit the same test. The test is marked out of 20. There are four students in each group. The table below shows the analysis of each group’s results. Group P Q R S T U Mean 14 14 15 15 15 14 Median 13 14 14 18 14 14 Mode 11 - 14 - 14 - Range 8 8 8 16 6 4 Using the information in the table, complete the statements below in order to compare ... 1. groups Q and R 2. groups P, Q and U 3. groups R, S and T. Use all of these statements each time to give a full comparison: On average, the [mean/median/mode/range] shows that … Using the [mean/median/mode/range], the spread of the results shows … Overall the most successful group was … because … Extension challenge Calculate the possible test results for each student in each group. Some groups may have more than one possible solution. (HINT: to start, work out each group’s total score.) © www.teachitmaths.co.uk 2011 16320 Page 1 of 4 Comparing the mean, median, mode and range Five groups of students – V, W, X, Y and Z – all sit the same test. The test is marked out of 20. There are five students in each group. The table below shows the analysis of each group’s results. Group V W X Y Z Mean 14 15 13 15 15 Median 12 16 15 16 14 Mode 12 - 15 - 14 Range 7 9 15 11 13 Using the information in the table, write a paragraph to compare how each group performed in the test. Use all of these statements to give a full comparison: – On average, the [mean/median/mode/range] shows that … Using the [mean/median/mode/range], the spread of the results shows … Overall the most successful group was … because … Overall the least successful group was … because … Extension challenge Calculate the possible test results for each student in each group. Some groups may have more than one possible solution. (HINT: to start, work out each group’s total score.) © www.teachitmaths.co.uk 2011 16320 Page 2 of 4 Comparing the mean, median, mode and range P, Q, R, S, T & U - possible answers Comparing Q and R On average, the mean shows that group R was more successful. Using the range, the spread of the results shows that both groups were equally consistent. Overall the most successful group was R because its mean score was higher. Comparing P, Q and U On average, the mean shows that all three groups performed the same but Q and U had a higher median so therefore performed better than group P. Using the range, the spread of the results shows group U’s results were most consistent. P and Q were as consistent as each other. Overall the most successful group was U because it had the joint highest median and its scores were the most consistent. However, P had the joint highest median and a larger spread, meaning one of its students may have had the highest score overall. Comparing R, S and T On average, the mean shows that all three groups performed the same. The median shows that S performed better than R and T. Using the range, the spread of the results shows group S was very inconsistent. However group S had the highest median, perhaps showing that three members performed well, with one student getting an abnormally low mark. Group T was more consistent as its range was smaller than the other two groups. Overall the most successful group was S because their median score was much higher than the others. In this case, the range may be confusing as it is affected by extreme values. Extension challenge – possible solutions Group Marks P 11 11 15 19 Q 10 12 16 18 R 12 14 14 20 S 4 17 19 20 T 13 14 14 19 U 12 13 15 16 © www.teachitmaths.co.uk 2011 16320 Page 3 of 4 Comparing the mean, median, mode and range W, X, Y and Z – possible answers On average, the mean shows that groups W, Y and Z were more successful because their means were the highest. The median shows that W and Y performed better than Z. Using the range, the spread of results shows that group V was the most consistent. The least consistent group was X. Overall the most successful group was W because, although its mean and median score was the same as Y, the range shows that the group as a whole was more consistent. However, it is likely that the individual student with the highest mark would appear in one of the groups with a larger spread. Overall the least successful group was X because its mean score was the lowest. The range also shows X to be the least consistent, meaning this group would have had one student with a very low score. Extension challenge – possible solutions Group Marks V 12 12 12 15 19 W 9 15 16 17 18 X 2 15 15 16 17 Y 8 14 16 18 19 Z 7 14 14 20 20 © www.teachitmaths.co.uk 2011 16320 Page 4 of 4