Consider n pairs of numbers. Suppose xˉ=4,sx=3,yˉ=2, and sy=5.Of the following which could be the least squares line?(A) y=2+x(B) y=−6+2x(C) y=−10+3x(D) y=5/3−x(E) y=6−x
Q. Consider n pairs of numbers. Suppose xˉ=4,sx=3,yˉ=2, and sy=5.Of the following which could be the least squares line?(A) y=2+x(B) y=−6+2x(C) y=−10+3x(D) y=5/3−x(E) y=6−x
Calculate slope using formula: Calculate the slope m of the least squares line using the formula m=nΣ(x2)−(Σx)2nΣ(xy)−ΣxΣy. We don't have Σ(xy) or Σ(x2), but we can use the correlation coefficient formula r=sx∗sysxy where sxy can be derived as sxy=r∗sx∗sy. Assume r=1 for maximum positive correlation, then sxy=1∗3∗5=15.
Calculate Σx and Σy: Calculate Σx and Σy using n, xˉ, and yˉ. Σx=n×xˉ=n×4, Σy=n×yˉ=n×2. We still need n to find exact values, but we can use these expressions in our slope formula.
Substitute values into formula: Substitute sxy, Σx, and Σy into the slope formula. Assuming n=10 for calculation: m = rac{(10 imes 15 - 4 imes 10 imes 2 imes 10)}{(10 imes 9 - (4 imes 10)^2)} = rac{(150 - 800)}{(90 - 1600)} = rac{-650}{-1510} = 0.43 approximately.