STAtistics / Mr. Hansen
HW due 4/1/2008, 2/27/2009

Name: ______________________

1.

Read recommendations 39 through 45 (pp. 26-27) and the standards of evidence (pp. 110-113) from the recently released NMAP report (National Mathematics Advisory Panel). For goodness’ sake, do not print out the entire document. Simply read pages xxvi and xxvii that contain the research recommendations, plus pages 82-85 (which are numbered 110-113 by Adobe Acrobat). Then answer the following questions.

 

 

2.

Translate the last sentence of the first paragraph of recommendation 40 (i.e., the sentence that talks about adequate statistical power) into layperson’s language. You may need to split this sentence off into a small paragraph of its own to make it understandable. Do not go into too much detail, and whatever you do, don’t use the term “Type II error.” My reason for making this assignment is that I predict that some of the readers of the report, even some who have math or math ed degrees, will not understand the sentence properly.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.

Do you agree or disagree with recommendation 45? Write a short paragraph supporting your opinion.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.

From p. 82 (numbered 110 in Acrobat), we know that the NMAP reviewed more than 16,000 (!) research studies but found few of them worthy. How would the NMAP standards of evidence rate each of the following?

 

 

(a)

Two sections of STA sophomores, with 15+14 students, are taught traditional Algebra II by Mr. X. The other two sections, with 13+18 students, are taught by Ms. Y using an experimental textbook. At the end of the year, all four sections are given the same final exam. Scores for Ms. Y’s students are found to be higher on average. There is no attrition. Compute the one-tailed P-value using your calculator, and determine the NMAP rating. Assume that neither class exhibits pronounced skewness or outliers.

Statistics for Mr. X: n = 29, =75.1, s = 9.8.
Statistics for Ms. Y: n = 31, =79.6, s = 10.7.

P = __________________

NMAP rating = __________________________

Rationale for NMAP rating: ________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

 

 

(b)

Two sections of STA juniors, Mr. Z’s students, are randomly assigned to receive instruction in logarithms (to which they have had no prior exposure) by one of the following protocols: either traditional instruction, in which they receive assignments from Mr. Z and listen to his explanations in class, or modified instruction, in which they receive the same assignments but are excused during class time to do whatever they wish. At the end of the experiment, all students are given the same exhaustive battery of standardized tests on logarithms, and their scores are compared. There is no attrition. Compute the two-tailed P-value and determine the NMAP rating. Give specific rationales for your decision. Assume that neither group exhibits pronounced skewness or outliers.

Statistics for traditionally instructed students: n = 14, =347, s = 44.3.
Statistics for “modified instruction” students: n = 16, =344, s = 46.2.

P = __________________

NMAP rating = __________________________

Rationale for NMAP rating: ________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

 

 

(c)

Is the hypothetical study in part (a) a controlled experiment? ________

Write a conclusion for the study in part (a): _________________________________________

______________________________________________________________________________

______________________________________________________________________________

 

 

(d)

Is the hypothetical study in part (b) a controlled experiment? ________

Write a conclusion for the study in part (b): _________________________________________

______________________________________________________________________________

______________________________________________________________________________