Question 509051: whats is the mean, maiden
Answer by bucky(2189)   (Show Source):
You can put this solution on YOUR website! You meant to say, what is the mean and the median.
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The mean is the average. You get it by adding up all the data and dividing the total by the number of elements of data. Example. If the scores on the test are 60, 80, 90, 75 and 50, the mean is found by adding 60 + 80 + 90 + 75 and +50 and dividing the sum by the number of tests taken (that is divide by 5 in this example). So the average is:
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Adding the scores together results in this becoming:
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and when you do the division you find out that the average or mean score on the test was 71.
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The median is another measure. It is found by arranging the data in order from the lowest value to the highest value, and then going from the lowest value upward until the middle value is found. For the above example, arrange the test scores from the lowest value to the highest value as follows:
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50, 60, 75, 80, 90
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The median is 75 because it is the middle of the scores. There are two scores above 75 and two scores below 75. So 75 is the median score.
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If you have an even number of data points, you find the median in a little different way. You find the two scores in the middle and average them. For example, suppose that we had the following test scores:
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40, 50, 60, 75, 80, 85, 90, 95
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Note that they are arranged from the lowest score up to the highest score. Note also that there are 8 scores, an even number. Therefore there are two middle scores, 75 (which has three scores below it) and 80 (which has three scores above it). There is no single score that has the same number of scores below it as above it.
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So we can say that the median score is half way between 75 and 80. We can find that half way point by averaging the two scores. So we add 75 to 80 and divide by 2. The addition of 75 and 80 results in 155 and dividing that sum by 2 results in an answer of 77.5 for the median.
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Remember that for finding the median you always arrange the data in increasing order and then start at the low value and go upward to the middle. If you have an odd number of data, the median will be the one in the middle of the data. It will have an equal number of data points below it as it has above it. If you have an even number of data, you will have two values in the middle that have the same number of data below them as they do above them. Once you have those two data elements identified, you average them to find the median.
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Hope this helps you to understand the difference between the mean and the median and the two possible ways to calculate the median that depend on whether you have an odd number of data or and even number.
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