Assignment
QMT412 Pn. Sanizah's Notes
02/05/2013
1 sanizah@tmsk.uitm.edu.my 2
CHAPTER 5 CORRELATION AND REGRESSION
Introduction Correlation and Regression Scatter Plot/Diagram Coefficient of Correlation Simple Linear Regression sanizah@tmsk.uitm.edu.my Learning objectives
• Explain the concept of correlation • Calculate Pearson’s correlation coefficient and interpret the results • Calculate Spearman’s rank correlation for qualitative and quantitative data and interpret the results • Determine the regression equation for a set of data and interpret the equation • Use the regression equation to forecast
3 sanizah@tmsk.uitm.edu.my sanizah@tmsk.uitm.edu.my
4
Introduction
• Correlation: Do you have a relationship? (Between two quantitative variables, x & y) • If you have a relationship:
▫ 1) What is the direction? (+ or -) ▫ 2) What is the strength (r: -1 to +1) #Correlation measures LINEAR relationship. If you have a significant correlation: How well can you predict a subject’s y-score if you know their x-score?
Correlation & Regression
• Regression and correlation are two concepts used to describe the relationship between variables. ▫ Correlation is a statistical method used to determine if a relationship between variables exists. ▫ Regression is the statistical method used to describe the nature of the relationship between variables - that is, positive or negative, linear or nonlinear.
1
QMT412 Pn. Sanizah's Notes
02/05/2013
5
6 sanizah@tmsk.uitm.edu.my Independent and Dependent Variable
• In this chapter, we want to study the relationship between 2 variables only. ▫ Independent variable – x ▫ Dependent variable - y • For example: ▫ Expenditure (x) and Revenue (y) ▫ Price (x) and sales (y) ▫ Number of days absent (x) and CGPA (y) ▫ Age of a person (x) and his/her blood pressure (y)
sanizah@tmsk.uitm.edu.my
Independent and Dependent Variable
Independent variable (x)
• Also called predictor or explanatory or
02/05/2013
1 sanizah@tmsk.uitm.edu.my 2
CHAPTER 5 CORRELATION AND REGRESSION
Introduction Correlation and Regression Scatter Plot/Diagram Coefficient of Correlation Simple Linear Regression sanizah@tmsk.uitm.edu.my Learning objectives
• Explain the concept of correlation • Calculate Pearson’s correlation coefficient and interpret the results • Calculate Spearman’s rank correlation for qualitative and quantitative data and interpret the results • Determine the regression equation for a set of data and interpret the equation • Use the regression equation to forecast
3 sanizah@tmsk.uitm.edu.my sanizah@tmsk.uitm.edu.my
4
Introduction
• Correlation: Do you have a relationship? (Between two quantitative variables, x & y) • If you have a relationship:
▫ 1) What is the direction? (+ or -) ▫ 2) What is the strength (r: -1 to +1) #Correlation measures LINEAR relationship. If you have a significant correlation: How well can you predict a subject’s y-score if you know their x-score?
Correlation & Regression
• Regression and correlation are two concepts used to describe the relationship between variables. ▫ Correlation is a statistical method used to determine if a relationship between variables exists. ▫ Regression is the statistical method used to describe the nature of the relationship between variables - that is, positive or negative, linear or nonlinear.
1
QMT412 Pn. Sanizah's Notes
02/05/2013
5
6 sanizah@tmsk.uitm.edu.my Independent and Dependent Variable
• In this chapter, we want to study the relationship between 2 variables only. ▫ Independent variable – x ▫ Dependent variable - y • For example: ▫ Expenditure (x) and Revenue (y) ▫ Price (x) and sales (y) ▫ Number of days absent (x) and CGPA (y) ▫ Age of a person (x) and his/her blood pressure (y)
sanizah@tmsk.uitm.edu.my
Independent and Dependent Variable
Independent variable (x)
• Also called predictor or explanatory or