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Range<br />Mode<br />Median<br />Mean<br />What do they <br />all mean?<br />
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NEED TO KNOW!<br />ALWAYS ARRANGE THE VALUES IN A DATA SET IN ASCENDING (LEAST TO GREATEST) ORDER BEFORE SOLVING FOR RANGE, MODE, MEDIAN AND MEAN.<br />
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Range<br />measure of dispersion (spread)<br />obtained by subtracting the smallest value fromthelargestvalue<br />14, 17, 17, 21, 25, 28, 28, 28, 33<br />highest value = 33 <br />lowest value = 14<br />range = 33 – 14 = <br />19<br />
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Central Tendency<br />single numerical value used to describe the average or typical value in a set of values<br />3 measures of central tendency<br />mode<br />median<br />mean<br />
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Mode<br />most frequent or popular value in a data set<br />determined by inspection<br />14, 17, 17, 21, 25, 28, 28, 28, 33<br />mode = <br />(get 28 three time, get 17 twice and all other values only once)<br />28<br />
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Median<br />counting average<br />the middle score<br />14, 17, 17, 21, 25, 28, 28, 28, 33<br />median = <br />With an odd number of values, the median is the middle value. However, with an even number of values, there are two middle values. Since the median can only be a single value, the median will have to be calculated with an even number of values. How can this be done?<br />25<br />
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Median cont’d<br />to figure out the median with an even number of values<br />find the two middle values<br />find the average of these values by adding the two values together and dividing by two<br />14, 17, 17, 19, 21, 25, 28, 28, 28, 33<br />two middle numbers = 21 & 25<br />21 + 25 = 46<br />median = 46 ÷ 2 = <br />23<br />
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Mean<br />arithmetic average<br />most widely used measure of central tendency<br />calculate by adding all the values together and dividing by the number of values<br />14, 17, 17, 21, 25, 28, 28, 28, 33<br />14+17+17+21+25+28+28+28+33 = 211<br />mean = 211 ÷ 9 = <br />23.4<br />
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REMEMBER<br />ALWAYS ARRANGE THE VALUES IN A DATA SET IN ASCENDING (LEAST TO GREATEST) ORDER BEFORE SOLVING FOR RANGE, MODE, MEDIAN AND MEAN.<br />
13.
Amy works for a record store. For the past two weeks, she has kept track of the number of records that have sold each day.<br />Find the range, mode, median and mean of this data.<br />
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