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Billy’s math test scores are 90, 92, 69, 76, 93, and 84.
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Find the range and interquartile range of his scores.
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First, we list numbers from least to greatest.
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Our next step would be to find the median.
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Now, there are six numbers here, which means a middle number wouldn’t really be listed.
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So we’re gonna have to find it.
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So what number is in the middle of 84 and 90?
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That would be 87.
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So 87 is our median; it’s the middle of this list.
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Next, we find the quartiles: the lower quartile and upper quartile.
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Now to the left of the median, there are three numbers.
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So 76 is our lower quartile.
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To the right of our median, there are three numbers; that means 92 is our upper quartile.
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Now we have everything that we need to answer our question.
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It says, “Find the range and the interquartile range of his scores.”
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In order to find the range, we simply subtract the largest number and the smallest number.
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So 93 minus 69, which means our range is 24.
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The interquartile range is where you take the upper quartile and subtract the lower quartile, which would be 92 minus 76.
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So our interquartile range would be 16.