Question

Use the sample data below to answer the following question(s). The paired data consist of the cost of regionally advertising (in thousands of dollars) a certain pharmaceutical drug and the number of new prescriptions written (in thousands). submit the file includes the outcomes from excel

Cost	9	2	3	4	2	5	9	10
Number	85	52	55	68	67	86	83	73

1. Find the value of the linear correlation coefficient r.
2. Find the equation of the regression line, letting cost be the independent (x) variable.
3. Find the coefficient of determination.
4. Find the standard error of estimate s_e.

Answer 1

	Cost X	Number Y	X * Y
	9	85	765	81	7225
	2	52	104	4	2704
	3	55	165	9	3025
	4	68	272	16	4624
	2	67	134	4	4489
	5	86	430	25	7396
	9	83	747	81	6889
	10	73	730	100	5329
Total	44	569	3347	320	41681

r = 0.708

Equation of regression line is


b = 2.788

a =( 569 - ( 2.7885 * 44 ) ) / 8
a = 55.788
Equation of regression line becomes

Coefficient of Determination

Explained variation = 0.501* 100 = 50.1%
Unexplained variation = 1 - 0.501* 100 = 49.9%

	Y
	85	80.88462	16.93639053
	52	61.36538	87.71042899
	55	64.15385	83.79289941
	68	66.94231	1.118713018
	67	61.36538	31.74889053
	86	69.73077	264.6878698
	83	80.88462	4.474852071
	73	83.67308	113.914571
Total	569	569	604.3846154

Unbiased Estimator of
Standard Error of Estimate