Question

what are the 4 methods of finding mean​

Answer 1

Methods to find mean for class 10 Is

Direct Method

This is the shortest and simplest method to calculate the arithmetic mean of a grouped data set. The steps are as follows

Prepare a table containing four columns.

In column 1 write the class interval.

In column 2 write the corresponding class marks (midpoint of the class interval) denoted by xi

In column 3 write the corresponding frequencies (fi) of the class intervals

In column 4 write the product of column 2 and column 3 which is denoted by xifi

Calculate Mean by the Formula Mean = ∑xifi / ∑ fi

Assumed Mean Method

Also called the shift of origin method, this method is used when the calculation by the direct method becomes very tedious. Steps to be followed are,

Prepare a table containing five columns

Write the class intervals in column 1

Write the corresponding class marks in column 2, denoted by xi.

Take the central value from amongst the class marks as the Assumed Mean denoted as A.

In column 3 calculate the deviations, i.e. di = xi – A

In column 4 write the frequencies (fi) of the given class intervals

In column 5 find the mean of di using formula Mean of di = ∑xidi / ∑ di

To finally to calculate the Mean, we add the assumed mean to the mean of the di

Step deviation method

This is also called the shift of origin and scale method. Steps to be followed are

Prepare a table containing five columns

Write the class intervals in column 1

Write the corresponding class marks in column 2, denoted by xi.

Take the central value from amongst the class marks as the Assumed Mean denoted as A.

In column 3 calculate the deviations, i.e. di = xi – A

In column 4 calculate the values of ui, ui= di/h, where h is the class width.

In column 5 write the frequencies (fi) of the given class intervals

Calculate the product of Column 4 and column 5, which is fiui

Find the Mean of ui = ∑xiui / ∑ ui

To find the mean we add the assumed mean A to the product of class width (h) with mean of ui

Answer 2

short cut method

step deviation method

direct method

sum of all observations/ no of observations