1. DATA ANALYSIS
20 NOVEMBER 2014

2. THEORY, PROPOSITIONS, LOGIC

3.  Hypotheses are“tested”
 Hypotheses are never“proved”
 Hypotheses only are“rejected”
 Theories are built and verified by testing hypotheses

4. Truth
Ho true Ho false
Decision
Fail to
reject Ho
Reject Ho

5. Error
Error
Truth
Ho true Ho false
Decision
Fail to
reject Ho
Reject Ho

6. Type 1
error
Type 2
error
Truth
Ho true Ho false
Decision
Fail to
reject Ho
Reject Ho

7. TRADITIONALLY,
probability of Type 1
error set at .05
Minimize Type 2
error by
increasing
sample size
Truth
Ho true Ho false
Decision
Fail to
reject Ho
Reject Ho

8. Fitting a straight line through a swarm of bivariate data

9. Y = a + bx

10. Y
Y =  + X
X
(x, y)
e
b = y / x
a y = a + bx + e

11.  Is there no relationship between Y and X in
the population?
• H0: yx = 0
 Is the slope of the line = 0 in the population?
• H0:  = 0

12.  Null hypothesis is H0: yx = 0
 Alternate hypothesis is H1: yx ≠ 0
 a = .05 Y =  + X

13.  Null hypothesis is H0:  = 0
 Alternate hypothesis is H1:  ≠ 0
 a = .05 Y =  + X

14. Rscript
Attaches mtcars and examines its characteristics

15. Rscript
Console

16. Rscript
Console
a b

17. Rscript
Console

18. Rscript
Console

19. Rscript
Console

20. Rscript
Console

21. Rscript
Plot

22. DATA ANALYSIS
20 NOVEMBER 2014