Question

In a classroom of 20 students, a physics test was conducted. The test was of 50 marks and the marks obtained by students are as follows

$$\begin{array}{cc}\text{Marks}& \text{Frequency}\\ 30& 4\\ 25& 5\\ 45& 6\\ 47& 2\\ 48& 1\\ 49& 1\\ 50& 1\end{array}$$

Calculate the mean for the given set of data.

• A. 35.8
• B. 36.8
• C. 37.8
• D. 38.8

Answer 1

The correct option is C

37.8

We can observe from the table that, 4 students have secured 30 marks, 5 students have secured 25 marks and so on.

Now, we have to add 30 four times, since 4 students have scored 30. Similarly, the number 25 must be added 5 times, and so on

$\therefore \text{Average}=\frac{30\times 4+25\times 5+45\times 6+47\times 2+48\times 1+49\times 1+50\times 1}{20}=37.8$.

So, the class average = 37.8