Consider the following data :
| Year | 2012 | 2013 | 2014 | 2015 | 2016 |
| Sales (in ₹ crores ) | 9 | 18 | 21 | 29 | 38 |
A straight line trend by the method of least square is :
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → $y=23+6.9x$
To find the straight-line trend,
$y=a+bx$
$∑y=9+18+21+29+36=115$
$∑x=-2+(-1)+(0)+(1)+(2)=0$
$∑xy=-18-18+0+29+76=69$
$∑x^2=(4)+(1)+(0)+(1)+(4)=10$
$a=\frac{∑y}{n}=\frac{115}{5}=23$
$b=\frac{∑xy}{∑x^2}=\frac{69}{10}=6.9$
$∴y=23+6.9x$