Representative values

Representative values

We have come across situtations where we use the term ‘average’ in our day-to-day life. Consider the following statements.

● The average temperature at Chennai in the month of May is 40° c.

● The average marks in mathematics unit test of class VI is 74.

● Mala’s average study time is 4 hours.

● Mathan’s average pocket money per week is ₹ 100.

We come across many more statements of such kind in our daily life. Let us take the example, “the average marks scored by class VI students in maths test is 74”. Does it mean that every student has scored 74? No, certainly not. Some students would have got more than 74 and some students would have got less than 74. Average is the value that represents the general performance of class VI students in maths test.

Similarly, 40° c is the representative temperature of Chennai in the month of May which does not mean that everyday temperature is 40º c in the month of May. Since the average lies between the highest and the lowest value of the given data, we say average is a measure of central tendency of the group of data. Different forms of data need different forms of representative or central value to describe it. We study three types of central values of data namely Arithmetic Mean, Mode and Median in this chapter.

Try these

Collect the height of students of your class. Organise the data in ascending order.

Solution:

Height of 15 students in our class.

130cm, 150 cm, 155 cm, 142 cm, 138 cm, 145 cm, 148 cm, 147 cm, 148cm, 143 cm, 141cm, 152 cm, 147 cm, 139 cm, 155 cm.

Ascending order :

130cm, 138cm, 139cm, 141cm, 142cm, 143cm, 145cm, 147cm, 147cm, 148cm, 148 cm, 150cm, 152 cm, 155cm, 155cm.