• # question_answer 22) The table below shows the salaries of 280 persons: Salary (In thousand Rs.) No. of Persons 5 ? 10 49 10 ? 15 133 15 ? 20 63 20 ? 25 15 25 ? 30 6 30 ? 35 7 35 ? 40 4 40 ? 45 2 45 ? 50 1 Calculate the median salary of the data.

 Salary No. of Persons Cumulative frequency (c.f.) 5 ? 10 49 182 15 ? 20 63 245 20 ? 25 15 260 25 ? 30 6 266 30 ? 35 7 273 35 ? 40 4 277 40 ? 45 2 279 45 ? 50 1 280 Total 280 $\frac{N}{2}=\frac{280}{2}=140$ The cumulative frequency just greater than 140 is 182. $\therefore$ Median class is 10 ? 15. $\Rightarrow$$l=10,h=5,N=280,\,c.f=49\,$ and $f=133$ Median $=1+\left( \frac{\frac{N}{2}-c.f.}{f} \right)\times h$ $=10+\left( \frac{140-49}{133} \right)\times 5$ $=10+\frac{91\times 5}{133}$ $=10+\frac{455}{133}$ $=10+3.42$ $=13.42$