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# Ex.14.2 Q9 Statistics Solution - NCERT Maths Class 9

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## Question

A company manufactures car batteries of a particular type. The lives (in years) of $$40$$ such batteries were recorded as follows:

 $$2.6$$ $$3.0$$ $$3.7$$ $$3.2$$ $$2.2$$ $$4.1$$ $$3.5$$ $$4.5$$ $$3.5$$ $$2.3$$ $$3.2$$ $$3.4$$ $$3.8$$ $$3.2$$ $$4.6$$ $$3.7$$ $$2.5$$ $$4.4$$ $$3.4$$ $$3.3$$ $$2.9$$ $$3.0$$ $$4.3$$ $$2.8$$ $$3.5$$ $$3.2$$ $$3.9$$ $$3.2$$ $$3.2$$ $$3.1$$ $$3.7$$ $$3.4$$ $$4.6$$ $$3.8$$ $$3.2$$ $$2.6$$ $$3.5$$ $$4.2$$ $$2.9$$ $$3.6$$

Construct a grouped frequency distribution table for this data, using class Intervals of size $$0.5$$ starting from the interval $$2 - 2.5.$$

Video Solution
Statistics
Ex exercise-14-2 | Question 9

## Text Solution

What is known?

• The life span (in years) of $$40$$ car batteries manufactured by a company.
• Class size is ‘$$0.5$$
• A class interval such as $$2-2.5$$

What is unknown?

• Constructing a grouped frequency distribution table with a class size of $$0.5.$$

Steps:

The required grouped frequency distribution table can be constructed as follows, with class intervals of ‘$$2-2.5$$’, ‘$$2.5-3$$’, ‘$$3-3.5$$’, ‘$$3.5-4$$’, and so on.

 LIFE SPAN OF BATTERIES (in years) NUMBER OF BATTERIES (frequency) $$2-2.5$$ $$2$$ $$2.5-3.0$$ $$6$$ $$3.0-3.5$$ $$14$$ $$3.5-4.0$$ $$11$$ $$4.0-4.5$$ $$4$$ $$4.5-5.0$$ $$3$$ TOTAL $$40$$

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