Q12 of 174 Page 585

The table given below gives the distribution of villages and their heights from the sea level in a certain region.





















Height (in meters)



200



600



1000



1400



1800



2200



No. of villages



142



265



560



271



89



16



Compute the mean height, using the step-deviation method.

Let the assumed Mean be A = 1400


= h = x2 – x1 = 600 – 200 = 400


Thus, we prepare the table as below:




















































Height (in meter)




No. of villages




=





200



142



-3



-426



600



265



-2



-530



1000



560



-1



-560



1400 = A



271



0



0



1800



89



1



89



2200



16



2



32




= 1343




= -1395



We know that,


Mean =


=


Hence, The Mean height is 984.51.


More from this chapter

All 174 →
10

Use the assumed-mean method to find the mean height of the plants from the following frequency-distribution table.



















Height in cm (xi)



61



64



67



70



73



No. of plants (fi)



5



18



42



27



8


 11

Use the step-deviation method to find the arithmetic mean from the following data.























X



18



19



20



21



22



23



24



F



170



320



530



700



230



140



110


 1

Find the median of

(i) 2, 10, 9, 9, 5, 2, 3, 7, 11


(ii) 15, 6, 16, 8, 22, 21, 9, 18, 25


(iii) 20, 13, 18, 25, 6, 15, 21, 9, 16, 8, 22


(iv) 7, 4, 2, 5, 1, 4, 0, 10, 3, 8, 5, 9, 2

 2

Find the median of

(i) 17, 19, 32, 10, 22, 21, 9, 35


(ii) 72, 63, 29, 51, 35, 60, 55, 91, 85, 82


(iii) 10, 75, 3, 15, 9, 47, 12, 48, 4, 81, 17, 27