The middle number of 1.5 and 7.1 can be calculated by finding the average of the two number. It is calculated to be 4.3.
An average is a single number taken as representative of a list of numbers, usually the sum of the numbers divided by how many numbers are in the list.
[tex]mean = \frac{sum\ of\ terms}{number\ of\ terms }\\ \\\frac{(1.5+7.1)}{2} = \frac{8.6}{2} = 4.3[/tex]
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