STAtistics Test #3, 10/23/2009 (Chapters 1-4)

STAtistics / Mr. Hansen
Test #3, 10/23/2009

Name: _______________________

Test #3 (Chapters 1-4)

Part I. Terminology (2 pts./box, 28 pts. total).
Fill in the blank boxes.

#	Description	Customary Name	Notation
1.	The number that forms the right edge of the box (not the whisker) in a boxplot
2.	The fraction (normally expressed as a decimal) of the variation in the response variable that can be explained by variation in the explanatory variable
3.	A non-resistant measure of spread (dispersion) for a sample; the units are the square of the units used for the underlying data measurements
4.	Population standard deviation	population s.d.
5.	One interpretation of the concept of “average” (i.e., central tendency)		M or Q₂
6.	The sum of the values in a univariate quantitative sample, divided by the sample size
7.	An effort to determine how robust the results or findings of a study are likely to be		N/A
8.	Mean squared deviation from the population mean		MSE
9.	Size of sample	sample size
10.	Computed LSRL intercept (on the AP exam)	LSRL intercept

Part II. Short Answer (8 pts. each, except for 17-19, which are 6 pts. each).
Show adequate work! Calculator notation is not permitted.

11. Approximately what percentage of the values in a normal distribution are between .5 and 3 standard deviations below the mean?

12a,b. If a student scores 77 on a Ms. Denizé test (mean 74, s.d. 8, normally distributed), what is his score as a z score? As a percentile?

13. Suppose that we have a univariate distribution in which 95% of the values lie within plus or minus 2 standard deviations of the mean. Can we conclude that the distribution is normal?

14. What is the meaning of the formula ? Write a short paragraph (2-3 sentences) in which you reveal a thorough understanding.

15. Define the words parameter and statistic.

16. Use the words parameter and statistic in a sentence that summarizes the essential nature of why we take a course in statistics.

17. Why would Nassim Nicholas Taleb (author of The Black Swan) say that looking at a sample of 100 days worth of stock market data is of no use whatsoever in evaluating the riskiness of a stock or even of a portfolio of stocks? Write a short paragraph indicating some thoughtfulness on the subject.

18. STA is one of only a small number of private high schools in the country that has a “need-blind” (or “needs-blind”) admissions policy. What form of bias is STA seeking to avoid, as described in Mr. Wilson’s assembly earlier this morning? Answer your question specifically in the statistical meaning of the term bias, not in the layperson’s usage of the term.

19. List two or three of the methodological procedures that would have to be in place in order for the policy in #18 to be successfully implemented.

20. What statistical meaning (explain the type of chart used and the way in which it is used) is represented by Mr. Wilson’s usage of the barbell symbol?

20 (ALTERNATE). State the Empirical Rule. Then, by using your calculator appropriately, determine (to the nearest tenth of a z score) the bounds for s.d. within which 90% of the values of a normal distribution could be found.