This math skill teaches how to find the necessary change in one number of a set to achieve a specific decrease in the mean of the set. Adjusting the value of this number affects the sum, thereby changing the overall mean.
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Find the change in the mean when a number is changed
Test your understanding of change in the mean when a number is changed by practicing it! Work through the below exercises to use it in practice.
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Let's change the 10 to decrease the mean by 2
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First we should find our original mean. The mean is the sum over the count, so our original mean is 9.
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Which means our new mean will be 7.
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If 4 numbers have a mean of 7, they must add up to 4 times 7, or 28. So 6 plus 14 plus 6 plus our new number equals 28.
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So 10 must change to 2 to reduce the mean by 2