All Exams Test series for 1 year @ ₹349 only
Question

What is the mean of the following distribution?
Marks1936606985
No. of Students6362591770

The correct answer is

52

Solution :- 

Calculating Mean from Marks and Frequency Data

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:

  • $x$ represents the values (Marks).
  • $f$ represents the frequencies (No. of Students).
  • $\sum (f \cdot x)$ is the sum of the products of each value and its frequency.
  • $\sum f$ is the sum of all frequencies (total number of students).

Data Organization and Calculation

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 ($f \cdot x$)
196$19 \times 6 = 114$
363$36 \times 3 = 108$
606$60 \times 6 = 360$
692$69 \times 2 = 138$
855$85 \times 5 = 425$


 

Summing the Values

Next, we calculate the sum of the 'No. of Students' column ($\sum f$) and the sum of the 'Product ($f \cdot x$)' column ($\sum (f \cdot x)$).

  • Total No. of Students ($\sum f$): $$ \sum f = 6 + 3 + 6 + 2 + 5 = 22 $$
  • Sum of Products ($\sum (f \cdot x)$): $$ \sum (f \cdot x) = 114 + 108 + 360 + 138 + 425 = 1145 $$

Mean Calculation

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.

Was this answer helpful?

Important Questions from Measures of Central Tendency

  1. What is mean deviation about the median ?

  2. The mode and median of a data is 26.7 and 71, respectively. What is the mean of the data? (Use empirical formula.)

  3. 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?

  4. The average of eight numbers is 14. The average of six of these numbers is 16. The average of the remaining two numbers is:

  5. The value of

    (1 + cot²θ)(1 + cosθ)(1 - cosθ) - (1 - sinθ)(1 + sinθ)(1 + tan²θ) is: (θ lies in the first quadrant)

Need Expert Advice?

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App