Question

Regression with data

	x	y	x-xmean	(x-xmean)2	y-ymean	(y-ymean)2	(x-xmean) (y-ymean)
	15	27	1.00	1.00	6.25	39.06	6.25
	11	12	-3.00	9.00	-8.75	76.56	26.25
	14	18	0.00	0.00	-2.75	7.56	0.00
	12	21	-2.00	4.00	0.25	0.06	-0.50
	20	28	6.00	36.00	7.25	52.56	43.50
	11	17	-3.00	9.00	-3.75	14.06	11.25
	13	29	-1.00	1.00	8.25	68.06	-8.25
	10	7	-4.00	16.00	-13.75	189.06	55.00
	16	22	2.00	4.00	1.25	1.56	2.50
	15	24	1.00	1.00	3.25	10.56	3.25
	17	34	3.00	9.00	13.25	175.56	39.75
	14	10	0.00	0.00	-10.75	115.56	0.00
SUM	168	249		90		750.25	179
Mean	14	20.75
Std. Dev.	2.86	8.26				r =	0.689
n	12	12				r =	0.689

Regression Directions:

Using the above table, work out the following:

1. Calculate r
2. Calculate b
3. Calculate a
4. Write the regression equation in y = a +bx format
5. Predict y where x = 5 (Question 4) and x=15 (Question5)

Answer 1

from above:

a)

r =0.6889

b) b=1.9889

c)a =-7.0944

d)y=-7.0944+1.9889x

e) for x=5,predicted value =-7.0944+1.9889*5=2.85

for x=15,predicted value =-7.0944+1.9889*15=22.74