Question

The frequency distribution of the marks obtained by $100$ students in a test carrying $50$ marks then the mean is

Marks	0-9	10-19	20-29	30-39	40-49
No. of students	8	15	20	45	12

• A. $28.3$
• B. $28$
• C. $27.3$
• D. $26.4$

Answer 1

The correct option is A $28.3$

Here the mean of given data is given by $\mu =\frac{\sum f_i{x}_i}{f_i}$,

Where $x_i$ are the mid values the mark range and $f_i$ are the corresponding frequencies or in this case the number of students.

$\therefore \mu =\frac{4.5\times 8+14.5\times 15+24.5\times 20+34.5\times 45+44.5\times 12}{8+15+20+45+12}$

$=\frac{2830}{100}$

$=28.30$

Hence, the answer is $\mathrm{28.30.}$