$A$ class consists of $50$ students out of which $30$ are girls. The mean of marks scored by girls in a test is $73$ (out of $100$) and that of boys is $71$. Determine the mean score of the whole class.

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.

$A$ child says that the median of $3, 14, 18, 20, 5$ is $18$. What does the child not understand about finding the median?

Following is the frequency distribution of total marks obtained by the students of different sections of Class $VIII.$

Marks	$100-150$	$150-200$	$200-300$	$300-500$	$500-800$
Number of students	$60$	$100$	$100$	$80$	$180$

Draw a histogram for the distribution above.

Find the mean of the first five prime numbers.

Find the mean and the median of the observations: $72, 15, 28, 31, 32, 51, 44, 43$ and $62$.