Question

The daily expenditure of 50 hostel students are as follows,Find the mean daily expenditure of the students of hostel using appropriate method.
Daily expenditure (in Rs.)
100-120
120-140
140-160
160-180
180-200

Number of students
12
14
8
6
10

Answer 1

Dear student,

Solution:

Daily Expenditure -- No. of students ---- class mark xi --- di = xi-a fidi

____________________________________________________________

100-120 --------------------12 ------------------------110 ------------ ( -40) ------ (-480)

120-140 ------------------ 14------------------------- 130 --------------(-20) -------- (-280)

140-160------------------- 8 ------------------------- 150-----------------(0) -------------(0)

160-180 ----------------- 6----------------------------170-------------- (20)---------- ( 120)

180-200 ---------------- 10------------------------ 190---------------- (40)----------- (400)

____________________________________________________________

Class mark x = (upper limit+ lower limit)/2

Assume a = 150

∑fi = 12+14+8+6+10 = 50

∑ fidi = -480-280+0+120+400 = -240

Assume mean method = a + (∑ fidi)/∑ fi

= 150 + (-240/50)

= 150- 4.8

= 145.20

Mean of the following data is = 145.20 rupees ≈ 145 Rupees

Hope it helps you.