Following is the daily expenditure on lunch by $30$ employees of a company:

| Daily Expenditure (in Rupees) | Number of Employees |
|-------------------------------|--------------------|
| $100$-$120

Question

Following is the daily expenditure on lunch by $30$ employees of a company:

| Daily Expenditure (in Rupees) | Number of Employees |
|-------------------------------|--------------------|
| $100$-$120$ | $8$ |
| $120$-$140$ | $3$ |
| $140$-$160$ | $8$ |
| $160$-$180$ | $6$ |
| $180$-$200$ | $5$ |

Find the mean daily expenditure of the employees.

Accepted Answer

Step 1: Using assumed mean method with $a = 150$:

| Class | $x_i$ | $f$ | $d$ | $fd$ |
|-------|-------|-----|-----|------|
| $100$-$120$ | $110$ | $8$ | $-40$ | $-320$ |
| $120$-$140$ | $130$ | $3$ | $-20$ | $-60$ |
| $140$-$160$ | $150$ | $8$ | $0$ | $0$ |
| $160$-$180$ | $170$ | $6$ | $20$ | $120$ |
| $180$-$200$ | $190$ | $5$ | $40$ | $200$ |
| | | $30$ | | $-60$ |
Step 2: Mean $= 150 + \frac{-60}{30} = 150 - 2 = 148$. Mean expenditure $=$ Rs. $148$.

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Solution