# Ex.14.4 Q5 Statistics Solution - NCERT Maths Class 9

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## Question

Find the mean salary of $$60$$ workers of a factory from the following table:

 Salary (in Rs.) Number of Workers $$3000$$ $$16$$ $$4000$$ $$12$$ $$5000$$ $$10$$ $$6000$$ $$8$$ $$7000$$ $$6$$ $$8000$$ $$4$$ $$9000$$ $$3$$ $$10000$$ $$1$$ Total 60

## Text Solution

What is known?

Salary of $$60$$ workers in tabular form

What is unknown?

Mean of the given data

Steps:

We know that

Mean $$=$$ \begin{align} \frac{{\sum {{f_i}{x_i}} }}{{\sum {{f_i}} }}\end{align}

The value of$$\sum {{f_i}{x_i}}$$   and  $$\sum {{f_i}}$$ f can be calculated as follows.

 Salary $$\left(x_{i}\right)$$ Number of Workers $$\left(f_{i}\right)$$ $$f_{i} x_{i}$$ $$3000$$ $$16$$ $$16 \times 3000=48000$$ $$4000$$ $$12$$ $$12 \times 4000=48000$$ $$5000$$ $$10$$ $$10 \times 5000=50000$$ $$6000$$ $$8$$ $$8 \times 6000=48000$$ $$7000$$ $$6$$ $$6 \times 7000=42000$$ $$8000$$ $$4$$ $$4 \times 8000=32000$$ $$9000$$ $$3$$ $$3 \times 9000=27000$$ $$10000$$ $$1$$ $$1 \times 10000=10000$$ Total $$\sum f_{i}=60$$ $$\sum f_{i} x_{i}=305000$$

Mean salary  \begin{align} = \,\frac{{305000}}{{60}}\end{align}

Therefore, mean salary of $$60$$ workers is $$\rm{Rs.}\, 5083.33.$$

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