Every parent cares about their children’s academic grades. Grades are calculated on their marks. But how many parents really understand the meaning of average marks ?

If there are 40 students in a class and the average mark is 70. If a student got 75 marks, will the parents grateful because the student are above average ?

If they thought that getting marks above the average means better off than half of the students, then they were seriously wrong. Take for an example:

If the marks for this 40 students are as follow:

100 – 1 ppl

95 – 2 ppl

90 – 4 ppl

85 – 10 ppl

80 – 12 ppl

75 – 1 ppl

35 – 3 ppl

30 – 2 ppl

20 – 5 ppl

The average mark is 70. However. students which scores below 75 marks are only 10 people, and students scores above 75 marks are 29 people. This means that the student who got 75marks ranks 30th of out 40. Is there anything to be grateful of ?

The reason of getting the results shown above, is because the scores have big differences. The average mark is not significant enough to reflect the rankings of the students.

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This entry was posted on Tuesday, May 29th, 2007 at 5:22 am and is filed under maths. You can follow any responses to this entry through the RSS 2.0 feed.
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