Consider the following data:

The equation of the straight line trend by the method of least squares is:

$y=9.2+0.7 x$

The correct answer is Option (3) - $y=9.2+0.7 x$

$\text{Take } x = -2,-1,0,1,2 \text{ for years } 2012,2013,2014,2015,2016$

$y = 8,10,7,9,12$

$\sum y = 46,\;\; \sum x = 0,\;\; \sum x^2 = 10$

$\sum xy = (-2)(8)+(-1)(10)+0(7)+1(9)+2(12)$

$= -16 -10 + 9 + 24 = 7$

$b = \frac{\sum xy}{\sum x^2} = \frac{7}{10} = 0.7$

$a = \frac{\sum y}{n} = \frac{46}{5} = 9.2$

$y = a + bx$

$y = 9.2 + 0.7x$

$x = \text{Year} - 2014$

$y = 9.2 + 0.7(\text{Year} - 2014)$

The trend equation is $y = 9.2 + 0.7(\text{Year} - 2014)$.