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Regression Analysis. ITK-226 Rancangan Percobaan Dicky Dermawan www.dickydermawan.net78.net dickydermawan@gmail.com. Regression Model. In many problems there are 2 or more variables that are related, and it is of interest to model or explore this relationship.
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Regression Analysis ITK-226 RancanganPercobaan DickyDermawan www.dickydermawan.net78.net dickydermawan@gmail.com
Regression Model In many problems there are 2 or more variables that are related, and it is of interest to model or explore this relationship. Suppose that there is a single dependent variable or response y that depends on k independent or regressorvariables, viz x1, x2,x3,… The relationship between these variables is characterized by a mathematical model called a regression model.
Model of Physical Properties Specific gravity of aqueous solution Density of mixture Boiling point correlation Density Heat capacity
Criteria for Best Fit Least sum of square error Error is the difference between measured value and model estimates.
Multiple regression: Factorial Design,Lost Data,Inacurate Levels In Design Factors When running a designed experiments, it is sometimes difficult to reach and hold the precise factor levels required by the design. Small discrepancies are not important, but large ones are potentially of more concern. Regression methods are useful in the analysis of a designed experiment where the experimenter has been unable to obtain the required factor levels.
Example The table shows a variation of the 23 factorial design where many of the test combinations are not exactly ones specified in the design. Most of the difficulty seems to have occurred with the temperature variable
Exercise Given the following data, fit the second order polynomial regression model:
Physical Situation:tank draining through an orifice in the bottom • How does the height of liquid vary with time? • How does the flow rate through the orifice vary with the depth of liquid? • How long will it take the tank to drain?
Physical Situation:tank draining through an orifice in the bottom Experimental data: Tank diameter 1 in Orifice diam. 0.043 in