Range, Mode, Median and MeanPresentation Transcript
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Range Mode Median Mean What do they all mean?
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NEED TO KNOW! ALWAYS ARRANGE THE VALUES IN A DATA SET IN ASCENDING (LEAST TO GREATEST) ORDER BEFORE SOLVING FOR RANGE, MODE, MEDIAN AND MEAN.
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Range measure of dispersion (spread) obtained by subtracting the smallest value fromthelargestvalue 14, 17, 17, 21, 25, 28, 28, 28, 33 highest value = 33 lowest value = 14 range = 33 – 14 = 19
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Central Tendency single numerical value used to describe the average or typical value in a set of values 3 measures of central tendency mode median mean
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Mode most frequent or popular value in a data set determined by inspection 14, 17, 17, 21, 25, 28, 28, 28, 33 mode = (get 28 three time, get 17 twice and all other values only once) 28
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Median counting average the middle score 14, 17, 17, 21, 25, 28, 28, 28, 33 median = 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? 25
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Median cont’d to figure out the median with an even number of values find the two middle values find the average of these values by adding the two values together and dividing by two 14, 17, 17, 19, 21, 25, 28, 28, 28, 33 two middle numbers = 21 & 25 21 + 25 = 46 median = 46 ÷ 2 = 23
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Mean arithmetic average most widely used measure of central tendency calculate by adding all the values together and dividing by the number of values 14, 17, 17, 21, 25, 28, 28, 28, 33 14+17+17+21+25+28+28+28+33 = 211 mean = 211 ÷ 9 = 23.4
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REMEMBER ALWAYS ARRANGE THE VALUES IN A DATA SET IN ASCENDING (LEAST TO GREATEST) ORDER BEFORE SOLVING FOR RANGE, MODE, MEDIAN AND MEAN.
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LET’S PRACTICE
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Find the range, mode, median and mean of this data set. 21, 18, 26, 30, 15, 26, 12, 18, 29, 26, 14, 23 First arrange the numbers in ascending order… 12, 14, 15, 18, 18, 21, 23, 26, 26, 26, 29, 30 range = 30 – 12 = 18 mode = 26 median = 21 + 23 = 44 ÷ 2 = 22 12+14+15+18+18+21+23+26+26+26+29+30 12 mean = 258 ÷ 12 = 21.5
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NOW FOR A STORY PROBLEM…
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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. Find the range, mode, median and mean of this data.
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Answers Put the numbers in order… 15, 17, 18, 19, 19, 19, 20, 22, 24, 25, 26, 28, 29, 30 range = 15 mode = 19 median = 21 mean = 22.2