Consider the following data :

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

$y=74+4.5x$

The correct answer is Option (2) → $y=74+4.5x$

The equation of the straight line trend is,

$y=a+bx$

$∑x=(-2)+(-1)+0+1+2=0$

$∑y=60+75+80+70+85=370$

$∑xy=(-2)(60)+(-1)(75)+(0)(80)+(1)(70)+(2)(85)=45$

$∑x^2=(-2)^2+(-1)^2+0^2+1^2+2^2=10$

$a=\frac{∑y}{n}=\frac{370}{5}=74$

$b=\frac{∑xy}{∑x^2}=\frac{45}{10}=4.5$

$⇒y=74+4.5x$