Given the data for the sales of a product in a state is as follows:

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

$162+14x$

The correct answer is Option (4) → $162+14x$

To find the equation of straight line trend,

$y=a+bx$

$∑x=(-2)+(-1)+0+1+2=0$

$∑y=150+150+160+170+200=810$

$∑xy=(-300)+(-150)+0+170+400=140$

$∑x^2=4+1+0+1+4=10$

$a=\frac{∑y}{n}=\frac{810}{5}=162$

$b=\frac{∑xy}{x^2}=\frac{140}{10}=14$

$y=162+14x$