post a questionThe data below represents the number of miles run during one week for a sample of $20$ runners.

Find the mean of the distribution. The grouped mean formula is given below$$

Class Frequency Midpoint fx

$5\mathrm{.}5-10\mathrm{.}51$

$10\mathrm{.}515\mathrm{.}52$

$15\mathrm{.}5-20\mathrm{.}53$

$20\mathrm{.}5-25\mathrm{.}55$

$25\mathrm{.}5-30\mathrm{.}54$

$30\mathrm{.}5-35\mathrm{.}53$

$35\mathrm{.}540\mathrm{.}52$

Note: the formula for group mean is $=$

$$

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where f is frequency, xm is the midpoint of x and

n is total frequenc