After arranging the observations in ascending or descending order,the observation which is obtained in the middle is called .............. of the data.

If the mean of $18, 2x, 27, 12, 3x, 5x$ and $21$ is $24,$ then find $x$.

Obtain the mean of the following distribution:

Frequency $(f_i)$	Variable $(x_i)$
$4$	$4$
$8$	$6$
$14$	$8$
$11$	$10$
$3$	$12$

The mean of the data: $2, 8, 6, 5, 4, 5, 6, 3, 6, 4, 9, 1, 5, 6, 5$ is given to be $5$. Based on this information,is it correct to say that the mean of the data: $10, 12, 10, 2, 18, 8, 12, 6, 12, 10, 8, 10, 12, 16, 4$ is $10$? Give reason.

If the information gathered by an investigator is from an already existing source of data,then such information is called .........

Represent the following data by means of a histogram:

Class	$0-5$	$5-10$	$10-20$	$20-30$	$30-50$	$50-70$
Frequency	$5$	$7$	$12$	$16$	$24$	$16$