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.
What is mean deviation about the median ?
The mode and median of a data is 26.7 and 71, respectively. What is the mean of the data? (Use empirical formula.)
Study the given table and answer the question that follows. The given table depicts the percentage of marks scored by Mary and Perul in History and Physics (out of 75 each).
| Name | History | Physics |
|---|---|---|
Mary | 60 | 64 |
Perul | 54 | 70 |
How many marks did Mary score in History?
The average of eight numbers is 14. The average of six of these numbers is 16. The average of the remaining two numbers is:
The value of
(1 + cot²θ)(1 + cosθ)(1 - cosθ) - (1 - sinθ)(1 + sinθ)(1 + tan²θ) is: (θ lies in the first quadrant)