Consider the following data of expenses (in lakhs) of an organization year wise
|
Year |
2001 |
2002 |
2003 |
2004 |
2005 |
|
Expenses (Rs. lakh) |
160 |
185 |
220 |
300 |
510 |
Then expected expenses trends for the year 2006 using method of least square is:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Rs. 519.5 lakh **
Given years: 2001–2005 and corresponding expenses:
$160,\;185,\;220,\;300,\;510$
Assign coded time values (least squares standard coding):
$t=-2,-1,0,1,2$ for years 2001–2005.
Compute required sums:
$\sum t = 0$
$\sum y = 160+185+220+300+510 = 1375$
$\bar{y} = 1375/5 = 275$
$\sum t^2 = 4+1+0+1+4 = 10$
$\sum ty = (-2)(160) + (-1)(185) + 0 + (1)(300) + (2)(510)$
$= -320 -185 + 0 + 300 + 1020 = 815$
Slope:
$b = \frac{\sum ty}{\sum t^2} = \frac{815}{10} = 81.5$
Intercept:
$a = \bar{y} = 275$
Trend equation:
$y = 275 + 81.5\,t$
For year 2006, $t=3$:
$y_{2006} = 275 + 81.5(3) = 275 + 244.5 = 519.5$
Expected expenses in 2006 ≈ ₹520 lakhs