FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICS I 5.7
Let A = 67. Now using the formula
x = A + fd ́
f
×i, we get 67.45 =
3
67 +^45 ×3
174 + f
or,
0.45^135
= 174 +f 3 or, 78.30 + 0.45 f 3 = 135
or, 0.45f 3 = 56.70 or, f 3 56.70
0.45
= = 126
For two missing frequencies :
Example 7: The A.M. of the following frequency distribution is 1.46
No. of accidents No. of days
0 46
1 f 1
2 f 2
3 25
4 10
5 5
Total 200
Find f 1 and f 2?
Let, x = No. of accidents, f = No. of days
Solution:
Table : Calculation of Mean
x f d = x – 2 fd
0 46 –2 –92
1 f 1 –1 –f 1
2 f 2 0 0
3 25 1 25
4 10 2 20
5 5 3 15
Total N = 200 –– Σfd= −32 f− 1
AM =
A + fd
f
or, 1.46 = 2 +^1
-32 - f
200 or, – 0.54
(32 f 1 )
200
=− +
or, 108 = 32 + f 1 , or, f 1 = 76,
f 2 = 200 – (46+ 76+ 25+ 10+ 5) = 38