Find the mean of the first seven natural numbers.

Draw a histogram for the following frequency distribution with unequal class length:

Class	$0-10$	$10-20$	$20-40$	$40-70$	$70-100$
Frequency	$15$	$13$	$28$	$36$	$27$

The mean marks (out of $100$) of boys and girls in an examination are $70$ and $73$,respectively. If the mean marks of all the students in that examination is $71$,find the ratio of the number of boys to the number of girls.

Expenditure on education of a country during a five-year period $(2002-2006)$,in crores of rupees,is given below:

Elementary education	$240$
Secondary education	$120$
University education	$190$
Teacher's training	$20$
Social education	$10$
Other educational programmes	$115$
Cultural programmes	$25$
Technical education	$125$

Represent the information above by a bar graph.

The median of the first ten natural numbers is .........

The median of the data $78, 56, 22, 34, 45, 54, 39, 54, 84$ is