Question

Following table gives age groupwise distribution of people suffering from 'Asthama' due to air pollution in certain city. Find mean age of person suffering from 'Asthama' .

Age (in years)	7 - 11	11 - 15	15 - 19	19 - 23	23 - 27	27 - 31	31 - 35	35 - 39
No. of People	5	9	13	21	16	15	12	9

• A. $23.88$years
• B. $24.88$ years
• C. $25.88$years
• D. $26.88$ years

Answer 1

Answer: (A)

$23.88$years

Consider the following table, to calculate mean:

$ci$	$f_i$	$x_i$	$f_i{x}_i$
7-11	5	9	45
11-15	9	13	117
15-19	13	17	221
19-23	21	21	441
23-27	16	25	400
27-31	15	29	435
31-35	12	33	396
35-39	9	37	333

$N=\Sigma f_i=100$

$\Sigma f_i{x}_i=2388$

Mean $\overline{x}=\frac{\Sigma f_i{x}_i}{N}$

$\therefore \overline{x}=\frac{2388}{100}=23.88$

Mean age of people suffering from Asthama is $23.88$years

Hence, option $A$ is correct.