Alinear regression equation is calculated for a sample of n = 20 pairs of x and y values.
what would be the df value for the standard error of estimate?

a) 19 b) 18 c) 2 d) 1

B) 18

Step-by-step explanation:

The degree of freedom for Standard error or df(Residual) is the sample size minus the number of estimated parameters ,.

df= n - p  , where n= sample size , p = number of parameters.

According to the given problem , we have

Sample size : n=20

Number of parameters (x and y ): p= 2

Then, the df value for the standard error of estimate will be :

df= n-p =20-2=18

Thus , the df value for the standard error of estimate is 18 .

Hence, the correct answer is B) 18 .

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4