Stat 11

February 13, 2006

Homework #4 (due Friday, February 17)

This homework is due at the start of class Friday, February 17. You may work in groups (across sections if you like), consult with others, or use any references or tools that seem useful, but you must write up your solutions yourself.

Problems from the text:

(Jargon from section 3.2 on experiments)

3.12

3.26 (statistical significance is defined on page 203; much more will be said about it)

(Kinds of samples)

3.36 For this problem, identify all four: POPULATION, SAMPLING FRAME, SAMPLE AS SELECTED, and ACTUAL SAMPLE. They’re all different. Also, say what the non-response rate is. (The text defines sampling frames in problem 3.55.)

3.48 (say why this sample fails to satisfy the definition of SRS)

3.52 (say why this sample fails to satisfy the definition of SRS)

(Bias and variability)

3.66

(A sampling distribution)

3.73 This problem uses the “probability” applet at the text’s website. (You could use the Excel worksheet from class, too, if you dare.) Set up the true probability (0.6), the sample size (25) and start pushing buttons. This would be a good problem to do in a group, but please draw your own histogram.

(Probability)

4.7 Pascal and Fermat really did work on this; it was harder for them than it is for you. You may use the applet if you like, OR you may construct any rational argument for why the probability of seeing a “6” is more than 50%, less than 50%, or exactly 50%.

4.13 (complement rule, probability of an “event”)

4.25 (essential knowledge for every probability student)

(end)