Chapter 7 Hypothesis Tests and Confidence Intervals in Multiple Regression
2 Outline
3 Hypothesis Tests and Confidence Intervals for a Single Coefficient in Multiple Regression (SW Section 7.1)
4 Example: The California class size data
5 Standard errors in multiple regression in STATA
6 Tests of Joint Hypotheses (SW Section 7.2)
7 Tests of joint hypotheses, ctd.
8 Why can’t we just test the coefficients one at a time?
9 Suppose t 1 and t 2 are independent (for this calculation).
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11 The F-statistic
12 The F-statistic testing 1 and 2 :
13 Large-sample distribution of the F-statistic
14
15 Computing the p-value using the F-statistic:
16 F-test example, California class size data:
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18 The “restricted” and “unrestricted” regressions
19 Simple formula for the homoskedasticity-only F-statistic:
20 Example:
21 The homoskedasticity-only F-statistic – summary
22 Digression: The F distribution
23 The F q,n–k–1 distribution:
24 Another digression: A little history of statistics…
25 A little history of statistics, ctd…
26 Summary: the homoskedasticity-only F- statistic and the F distribution
27 Summary: testing joint hypotheses
28 Testing Single Restrictions on Multiple Coefficients (SW Section 7.3)
29 Testing single restrictions on multiple coefficients, ctd.
30 Method 1: Rearrange (“transform”) the regression
31 Rearrange the regression, ctd.
32 Method 2: Perform the test directly
33 Confidence Sets for Multiple Coefficients (SW Section 7.4)
34 Joint confidence sets ctd.
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36 Confidence set based on inverting the F-statistic
37 An example of a multiple regression analysis – and how to decide which variables to include in a regression…
38 A general approach to variable selection and “model specification”
39 Digression about measures of fit…
40 Back to the test score application:
41 More California data…
42 Digression on presentation of regression results
43
44 Summary: Multiple Regression