Give the formula for finding out median of a continuous series.

Median class is identified. It corresponds to that cumulative frequency which includes the $\left(\frac{N}{2}\right)th$ item. The following formula is then applied to determine the actual median value.

$M=l_1+\frac{\frac{N}{2}-c.f.}{f}\times i$

(Here, $l_1=$ Lower limit of the median class; c.f. = Cumulative frequency of the class preceding the median class; f = Frequency of the median class; i = Size of the median class interval.)