Arithmetic Mean (A.M)

ARITHMETIC MEAN

The arithmetic mean, also popularly referred to as the ‘mean’ is the average of a series of figures or values.

It is obtained by dividing the sum of the figures by the total number of the figures or values.

Formula for calculating Arithmetic Mean

Arithmetic mean (Ẍ) = ∑X/n

Where X = arithmetic mean

∑ = ‘sigma’ which means ’sum of’

X = series of figures in a given data

∑x = the total of the values of series of figures in a given data

N = number of figures or elements

OR

Mean Deviation:

ADVANTAGES OF ARITHMETIC MEAN

1. Arithmetic mean is very easy to calculate
2. It gives an exact value
3. It is the best known average
4. It is very easy to understand
5. It provides a good market of comparing values
6. It makes use of all available information

DISADVANTAGES OF ARITHMETIC MEAN

1. Arithmetic mean cannot be obtained graphically
2. Certain facts in arithmetic mean may not be revealed
3. It may be difficult to obtain without calculation
4. It can lead to distorted result

Exercise:

A man is able to save N50.00 of his salary in a particular year.  After, every year he saved N20.00 more than the preceding year.  How long does it take him to save N4370?  JAMB

Assignment

1. The first and last terms of an A.P are 21 and -47 respectively. If the sum of the series is given as -234.  Calculate (a) the number of terms in the A.P  (b) the sum of the first 18 terms
2. Yusuf has just secured a job in a big company as a clerical officer. His starting salary is N180, 000 per annum with annual investment of N2, 000.  Determine his salary in the 20^th year and find his total salary he would have and in the first 20 yrs.