深圳大学管理学院：《运筹学》课程教学资源（PPT课件讲稿）决策与对策（决策论）运筹学3类 Business Decision Modelling

An Introduction To business Decision Modelling Chen Zhimin(陈智民) School of management Shenzhen University Office:文科楼2403 Tel:26534104(0)13902972552( Mobile Email:chenzm@szu.edu.cn

An Introduction To Business Decision Modelling Chen Zhimin(陈智民) School of Management Shenzhen University Office: 文科楼2403 Tel: 26534104(O) 13902972552(Mobile) Email: chenzm@szu.edu.cn

1. The structure of linear models The general expression for a straight line y=a+bX cRy and X: dependent /independent variables of interest CRa and b: constants, coefficients, parameters a: Intercept--- y=a+b(o=a b: Slope(Gradient) b=the change in y/unit change in x =△y△X

1. The Structure of Linear Models  The general expression for a straight line: y=a+bx y and x: dependent /independent variables of interest a and b: constants, coefficients, parameters  a: Intercept--- y=a+b(0)=a  b: Slope (Gradient) b=the change in y/unit change in x =y/ x

Diagram 1.1 y=3+2x 10 △y=2 9 △x=1 y 6 △y=2 Ax=1

EXample: y=3+2X inTercept: a=3 cR Slope:b=△y△X=2 Shifts of a straight line cR Changes in the intercept y=7+2x y=-2+2X CHAnges in the slope y=3+5 y=3+1X

 Example: y=3+2x Intercept: a=3 Slope: b=y/ x=2  Shifts of a straight line Changes in the intercept  y=7+2x  y=-2+2x Changes in the slope  y=3+5x  y=3+1x

TWo fundamental types of shifts of straight line pARallel shift: changes in the intercept pIvotal shift: changes in the slope

 Two fundamental types of shifts of straight line: Parallel shift: changes in the intercept Pivotal shift: changes in the slope

Diagram 1.2a Change in Interce pt(positive slope) 15 10 5 0 10

Diagram 1.2b Change in Interce pt (negative slope) 25 20 15 Q 0 67 10 10 15

Diagram 1.2a Change in Interce pt(positive slope) 25 20 15 5 0 3 5 6 8 9 10

Diagram 1.2b Change in Intercept(negative slope) 30 15 5 2 5 9 10 -10 15

D 3 n Slop 543 09876543210 y △y=之 987654321 △x= AyE 4