Week 7 (3/10/05 - 3/17/05)

Setting boundaries is a form of love. -- Fred Rogers (1928 - 2003)

UNIT 15 

• Grading key  
• Let's look at the water.sav analysis as review

Comments RE: UNIT 14 HW 

• Excellent job, continuing improvements
• Why I scrutinize some of your homework (Linda's  art history class) 
• Most serious error - missing analyses (rare) 
• Specific error -- you cannot reliably reliably determine strength from a scatterplot (unless all points fall directly on the line). See figure: Two scatter plots of same data. Straight-line pattern in lower plot appears stronger because of improper scaling and surrounding white space:  
• It is the statisticians responsibility to present data in a responsible way (e.g., yes, this require judgment, and trial and error, too)
• It really is OK not to calculate everything every time by hand (Did I show the trick for calculating SS from s²?)
• Summarize your analysis 
  • e.g., Unit 14 summaries should mention linearity, direction, strength, significance, outliers (if any)
  • A summary of  "significant" is rarely adequate or advisable (we talked about this in relation to the other chapters, too)
• Let's continue to work on the more accurate interpretation of p values, which is smaller p --> greater confidence in rejecting H0 (better information than using the artificial cutoff of .05 or .01 (We've discussed this in the past 5 classes, but I don't think its getting through to everyone.)

BREAK Please print this handout formulas1.pdf

Selected Methods and Interpretations

How to Prepare for the Exam