REGRESSION

What is regression?

Regression is a descriptive statistical technique for finding the best fitting straight line between two variables.

Regression line is drawn through the points to summarize the relationship between the variables.

Scatter Diagram is a graph drawn by two axes.

abscissa (x-axis)

ordinate (y-axis)

STUDENT

123456789

10

GRADES (Y)

89888277909180938186

HOURS SPENT (X)

2.52.751.51.03.02.5

1.253.51.52.0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

75

78

81

87

90

93

84

Trend line is a line by hand with the aid of a ruler.

Conditions of a good trend line:1. If it approximates the general

directions of the points.2. If it passes through the points.

Least Square Regression Line

The Least Square Regression Line

(LSRL) the best fitting trend line is used to have a common estimate by everyone

The Least Square Regression Line

(LSRL)FORMULA:

Y = dependent variableX = independent variablea = point on vertical axis through which the line passesb = slope of the line

Y = a +bX

x2y xyx y2

2.52.751.51.03.02.5

1.253.51.52.0

89888277909180938186

6.257.562.251.009.006.251.56

12.252.254.00

7921777467245929810082816400864965617396

222.5242.07123.077.0

270.0227.5100.0325.5121.5172.0

52.37585721.50 73 705 1 881

Thank YouandGOD

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