Marks 19 36 60 69 85 No. of Students 63 62 59 17 70
52
To find the mean of a frequency distribution, we need to sum the product of each value (Marks) and its corresponding frequency (No. of Students) and then divide by the total number of observations (total frequency).
The formula for the mean ($\bar{x}$) of a frequency distribution is:
$$ \bar{x} = \frac{\sum (f \cdot x)}{\sum f} $$
Where:
First, let's organize the given data into a table and calculate the product ($f \cdot x$) for each row:
| Marks ($x$) | No. of Students ($f$) | Product ($f \cdot x$) |
|---|---|---|
| 19 | 6 | $19 \times 6 = 114$ |
| 36 | 3 | $36 \times 3 = 108$ |
| 60 | 6 | $60 \times 6 = 360$ |
| 69 | 2 | $69 \times 2 = 138$ |
| 85 | 5 | $85 \times 5 = 425$ |
Next, we calculate the sum of the 'No. of Students' column ($\sum f$) and the sum of the 'Product ($f \cdot x$)' column ($\sum (f \cdot x)$).
Finally, we apply the formula using the sums calculated above:
$$ \bar{x} = \frac{\sum (f \cdot x)}{\sum f} = \frac{1145}{22} $$
Performing the division:
$$ \bar{x} \approx 52.045 $$
Rounding the result to the nearest whole number, the mean marks are approximately 52.
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