The following table gives the frequency distribution of trees planted by different Housing Societies in a particular locality: No. of Trees No. of Housing Societies 10-15 2 15-20 7 20-25 9 25-30 8 30-35 6 35-40 4 Find the mean number of trees planted by Housing Societies by using ‘Assumed Means Method’

By Assumed Mean Method No. of trees Class mark xi di=xi-A No of housing societies(fi) fidi 10-15 12.5 -10 2 -20 15-20 17.5 -5 7 -35 20-25 `22.5toA` 0 9 0 25-30 27.5 5 8 40 30-35 32.5 10 6 60 35-40 37.5 15 4 60 Total - - ` sumf_i=36` `sumf_id_i=105` `bar d=(sumf_id_i)/(sumf_i)=105/36=2.916` Mean = `bar x=A+bard` = 22.5 + 2.916 = 25.42 Therefore the mean number of trees planted by Housing Societies is 25.42.

The Following Table Gives the Frequency Distribution of Trees Planted by Different Housing Societies in a Particular Locality - Algebra

The following table gives the frequency distribution of trees planted by different Housing Societies in a particular locality:

No. of Trees	No. of Housing Societies
10-15	2
15-20	7
20-25	9
25-30	8
30-35	6
35-40	4

Find the mean number of trees planted by Housing Societies by using ‘Assumed Means Method’

Advertisement Remove all ads

Solution

By Assumed Mean Method

No. of trees	Class mark x_i	d_i=x_i-A	No of housing societies(fi)	f_id_i
10-15	12.5	-10	2	-20
15-20	17.5	-5	7	-35
20-25	`22.5toA`	0	9	0
25-30	27.5	5	8	40
30-35	32.5	10	6	60
35-40	37.5	15	4	60
Total	-	-	` sumf_i=36`	`sumf_id_i=105`