Find the mean from the following frequency distribution of marks at a test in statistics:

Marks $\left(\mathrm{x}\right)$ :	$5$	$10$	$15$	$20$	$25$	$30$	$35$	$40$	$45$	$50$
No. of students $\left(\mathrm{f}\right)$:	$15$	$50$	$80$	$76$	$72$	$45$	$39$	$9$	$8$	$6$

 

The following table gives the distribution of total household expenditure (in rupees) of manual workers in a city.

Find the average expenditure (in rupees) per household.

A survey was conducted by a group of students as a part of their environment awareness programme, in which they collected the following data regarding the number of plants in $20$ houses in a locality. Find the mean number of plants per house.

Which method did you use for finding the mean, and why?

Consider the following distribution of daily wages of $50$ workers of a factory.

Find the mean daily wages of the workers of the factory by using an appropriate method.

Thirty women were examined in a hospital by a doctor and the number of heart beats per minute recorded and summarized as follows. Fine the mean heartbeats per minute for these women, choosing a suitable method.

Find the mean of each of the following frequency distribution:

Find the mean of each of the following frequency distribution:

Find the mean of each of the following frequency distribution:

Find the mean of each of the following frequency distribution: