Finding Mean, Median, ModeDate: 03/29/98 at 18:29:10 From: Adam White Subject: Mean of scores I have been out of school for 8 years and I am trying to get my diploma. On one of my practice tests it said to get the mean, median, and mode of scores. However in my textbook there are no examples to show me how to do it. The scores are: 100, 78, 93, 84, 91, 100, 82, 79. I would greatly appreciate if someone would show me how to do them. Thank you, Adam Date: 03/29/98 at 20:40:34 From: Doctor Sam Subject: Re: Mean of scores Adam, The mean of the scores is another name for their average. Just add them up and divide by the number of scores: mean = (100+78+93+84+91+100+82+79)/8 = 88.375 The median of the scores is "the number in the middle" when the scores are sorted in order. In your example: 100 100 93 91 84 82 79 78 If there is an even number of scores (as in your example) there is no number in the middle so the two numbers in the middle are averaged: median = (91 + 84)/2 = 87.5 The mean of the numbers can be misleading. If I tell you the mean income in my neighborhood is 1 million dollars a year you might think that I am wealthy. But maybe the neighborhood is a poor one with one very rich person making many millions of dollars a year. The average will be large because one number is very large. The median and the mean together give a better idea of the spread of the numbers. If there were one really wealthy person then the median income would be quite low. In your case the median is quite near to the mean, which suggests that the spread is probably evenly balanced. The mode of a set of numbers is the number that occurs most often. In your example: mode = 100 The mode may help to correct false impressions if you know the mean and the median but don't actually see the data. For example, if I tell you the mean of four numbers is 50.5 and the median is 50 you may think that the four numbers are close to one another, like the numbers in your example. In fact, however, I am thinking of: 101 99 1 1 The mean is (101 + 99 + 1 + 1)/4 = 202/4 = 50.5 and the median = (99+1)/2 = 50. But the mode here is 1. If you know that, you will know that 1 is repeated more than once in the data and, since the mean is near 50 with only four numbers, that might give you the idea that the data include several large numbers and several small numbers rather than four numbers close to one another. I hope that helps. -Doctor Sam, The Math Forum Check out or web site! http://mathforum.org/dr.math/ |
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