Question

Based on the data shown below, use your graphing calculator or Excel to calculate the regression line (each value to two decimal places)

y = x +

x	y
1	27.98
2	26.51
3	27.44
4	25.97
5	21.8
6	23.53
7	22.56
8	18.19
9	18.72
10	16.15
11	15.68
12	11.71
13	10.84
14	9.47
15	9.6

Answer 1

Computational Table:

	X	Y	X2	Y2	XY
	1	27.98	1	782.8804	27.98
	2	26.51	4	702.7801	53.02
	3	27.44	9	752.9536	82.32
	4	25.97	16	674.4409	103.88
	5	21.8	25	475.24	109
	6	23.53	36	553.6609	141.18
	7	22.56	49	508.9536	157.92
	8	18.19	64	330.8761	145.52
	9	18.72	81	350.4384	168.48
	10	16.15	100	260.8225	161.5
	11	15.68	121	245.8624	172.48
	12	11.71	144	137.1241	140.52
	13	10.84	169	117.5056	140.92
	14	9.47	196	89.6809	132.58
	15	9.6	225	92.16	144
Total	120	286.15	1240	6075.38	1881.3

Calculator:

For Slope:

b = -1.46

For Intercept:

a = 19.1 - (-1.46 * 8)

a = 30.73

Therefore, the least square regression line would be,

= 30.73 - 1.46 (X)