Quantitative Methods 2017

Parametric statistics

• Necessary to validate assumption • Example: test for deviation from normality • Remember: p-value >0.05 not enough

Normal

Normal P-P Plot of GTVrad

1.0

Mean = 58.1428 Std. Dev. = 43.04318 N = 85

25.0

0.8

20.0

0.6

15.0

Frequency

0.4

10.0

Expected Cum Prob

0.2

5.0

0.0

0.0

.00

50.00

100.00

150.00

200.00

250.00

0.0

0.2

0.4

0.6

0.8

1.0

GTVrad

Observed Cum Prob