SSC MTS 6 Aug 2019 Shift 2 Paper

$\stackrel{\leftharpoonup }{\mathrm{x}}\left(\mathrm{mean}\right)=\frac{\mathrm{\Sigma }\mathrm{fx}}{\mathrm{n}}$
⇒ n = total frequency
$\sum \mathrm{fx}$ =Sum of the product of mid−interval values and their corresponding frequency
Mid value of 10 – 12 = (10 + 12)/2 = 11
Mid value of 12 – 14 = (12 + 14 )/2 = 13
Mid value of 14 – 16 = (14 + 16 )/2 = 15
Mid value of 16 – 18 = (16 + 18 )/2 = 17
Mid value of 18 – 20 = (18 + 20 )/2 = 19
⇒ $\mathrm{Mean}=\frac{11\times 6+13\times 8+15\times 5+17\times 7+19\times 4}{6+8+5+7+4}=\frac{440}{30}$
⇒ Mean = 14.67
∴The mean marks of the given data are 14.67