Transcript of "Measure of Central Tendency Bonsu& Warmsley"
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Measures of central tendency<br />Dominique Warmsley<br />& <br />Bettina Bonsu<br />March 29, 2010<br />Math 300-003<br />
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When you hear someone use the word “average” to describe a set of numbers, there are 3 ways you can describe data, all of which can be thought of as “measures of central tendency”<br /> 1. Mean <br /> 2. Median<br /> 3. Mode <br />
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Mean: A set of numbers is the sum of values divided by the number of values. We can write this as a formula.<br />Example: <br />These are the values <br />5 + 10 + 7+ 12 + 8 + 6= 48<br /> Add all the numbers<br />Then count all the values and then divide by number of<br />values. <br /> 48 divided by 6 = 8<br />So the mean for this set of values is 8<br />
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Work It out!<br />What is the Mean of this set 7,10, 8, 14, 6<br />Remember: follow all the steps!<br />
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Answer is:<br />7 + 10 + 8 + 14+ 6= 45<br />45 divided by 5 is ……… 9<br />So your mean is 9 <br />
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Median: a middle number of a set of numbers. You have to make sure your numbers are in order first.<br />Values need to be ordered least to greatest.<br />If the number of data values in the list is odd, then<br />the median is the middle number in the list.<br />If the number of data value is even, there is no single middle<br />number . So the median is the mean of the 2 middle numbers in the list.<br />
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Watch Me!!!<br />Example: <br />35, 74, 53, 98, 32,<br /> Place in order least to greatest<br />32, 35, 53, 74, 98 <br />The median is 53<br />There are 5 values (an odd #), so the median is the middle number.<br />
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Now I’ll watch you!<br />4200, 3600, 4500, 3500, 3800<br />Now put them in order, and find your <br />median<br />
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See it wasn’t that hard<br />The order least to greatest<br />3500, 3600, 3800, 4200, 4500<br />Because there are five data values <br />(an odd number) the middle number is<br />median. 3800 is the median. But you knew <br />that right.<br />
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It can also look like this …..<br />2600, 3900, 9800, 2200, 4100, 1500<br />Next step is least to greatest<br />1500, 2200, 2600, 3900, 4100, 9800<br />The middle # are….. 2600, 3900<br />you add both numbers 2600 + 3900 = 6500<br /> Then 6500 divided by 2 = 3250<br />Remember these steps……. <br />
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Now you can try this …..<br />Find the median of this value set:<br />26.08, 39.02, 98.07, 22.03, 41.04, 15.02<br />
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Solution…..<br />Find the median of this value set:<br />26.08, 39.02, 98.07, 22.03, 41.04, 15.02<br /> In order from smallest to largest:<br />15.02, 22.03, 26.08, 39.02, 41.04 ,98.07<br /> Taking the mean of the middle two values<br /> 26.08 + 39.02= 65.1 <br /> 65.1 divided by 2= 32.55<br />
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Mode: set of a value that occur most often.<br /> If two values occur most often we say the data is a bimodal.<br />If more than two values occur most often, we say there is no mode.<br />
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Data Sets<br />Example1:<br />6.3, 12.5, 2.3, 6.3, 1.2, 3.3, 6.3,<br />The data value 6.3 appears more often<br /> then any number . Therefore 6.3 is the <br />mode.<br />Example 2:<br />2, 12, 14, 67, 98, 6, 15, 13, 10<br /> No data value occurs most often, There is<br />no mode for this set.<br />
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Now you can try this …..<br />Find the mode of the value sets :<br />Pink, blue, silver, yellow, pink , blue , pink<br />6, 14, 13, 12, 14, 6, 5, 6, 10, 14, 2<br />2, 5, 10, 3, 6, 19, 11, 20, 19<br />
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Solution……<br />Find the mode of the value sets :<br />Pink, blue, silver, yellow, pink , blue , pink<br /> Mode is: pink<br />6, 14, 13, 12, 14, 6, 5, 6, 10, 14, 2<br />Bimodal sets are: 6, 14<br />2, 5, 10, 3, 6, 9, 11, 20, 19<br />Mode is: none <br />
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Food For Thought!<br />So, remember when you think average,<br />think a set a numbers . <br />And revisit your friends :<br />Mean <br />Median <br />Mode<br /> Remember math is your friend !<br /> Give him a hug<br />
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