Eco-10026 Lecture5 2016.pdf

Eco-10026 Lecture5 2016.pdf - Lecture 5 Data Analysis...

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Lecture 5: Data Analysis III (Relationships) Quantitative Methods 1: 1/33 ECO-10026 Quantitative Methods I Dr E. Symons R OOM DW 1.55, D ARWIN B UILDING e - mail: [email protected]
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Lecture 5: Data Analysis III (Relationships) Quantitative Methods 1: 2/33 Lecture Contents and Objectives Data Analysis III: Relationships between Pairs of Variables Much of science/social science concerned with discovering and measuring relationships: Gravity and mass Price and demand Interest Rate and Savings Burglary rate and Unemployment Need to have measures for: Discovering relationships, Measuring strength of relationships, “Summarising” relationships This lecture will consider: Relationships linear and non-linear Scatter Diagrams Covariance Correlation Regression Equations Ref: Swift&Piff Stats 3 p425-438; Bradley (Stats) Chap 3 p 113-159
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Lecture 5: Data Analysis III (Relationships) Quantitative Methods 1: 3/33 Yield and Fertilizer 0 10 20 30 40 50 60 70 80 90 0 100 200 300 400 500 600 700 800 Fertilizer Yield Scatter Diagrams. Visualise relationships between pairs of variables - useful starting point An Example Consider relationship between crop yield and fertilizer applications on fields. Here the experimenter has varied the fertilizer on each field… So Fertilizer is the INDEPENDENT variable (on X-axis) Yield is DEPENDENT variable (on Y-axis). Each spot shows combination of fertilizer and yield. Seven experiments Field Fertilizer (k/hectare) Yield (tonnes/hectare) 1 100 40 2 200 50 3 300 65 4 400 70 5 500 50 6 600 65 7 700 80
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