AP Statistics / Mr. Hansen	Name: _______________________________________
1/4/2011

Scoring Guide for Dec. 16 Test

Name.	Score 3 points if your name was legible. Everyone’s name was legible.
Bonus.	Add 1 point if you had 4 AAA batteries on the day of the test and showed them to Mr. Hansen. Approximately half the students earned the battery bonus for this test. Note: If you took both the Dec. 15 test and the Dec. 16 test, the battery bonus applies to at most one test, since only the higher of the two scores is being recorded. However, your metaknowledge bonus for each test is treated separately and is counted as extra credit (i.e., same as a Mathcross puzzle).
1.	A total of 24 points were possible in question #1, almost a quarter of the test. (a) Score 6 points for the words “sampling distributions.” Everyone earned these points on Dec. 16. (b) Score 10 points for a fully correct definition of sampling distribution. Deduct 1 point if the requirement of fixed n is not mentioned, 2 points if the words “all possible samples” are not present. Deduct at least 5 points (more in some cases) if the word “statistic” is missing from your definition. However, if you listed one statistic (say, ) instead of indicating that a sampling distribution could be the set of possible values for any statistic, deduct only 2 points. Deduct 10 points for saying (as some did) that a sampling distribution is the distribution of samples. (c) Score 2 points for mentioning the sampling distribution of . (d) Score 2 points for the words “sample mean.” (e) Score 2 points for mentioning the sampling distribution of . (No credit for saying p or .) (f) Score 2 points for the words “sample proportion.” Note: Some students referred to and instead of and . That is acceptable for full credit, as long as the terms were properly defined as standard deviations of the statistics in the sampling distributions. (You could also use the term “standard error” here.)
2.	(a) Score 4 points for the word “binomial.” No other answer is acceptable. There is no partial credit. (b) Score 2 points for “rules” or 1 point for “laws.” (c) Score 2 points for “thumb” or 1 point for listing all three rules. (The word “thumb” fits the blank better.) (d) Score 4 points for the word “normal” or the letter z. Deduct 1 point if the letter z is not crossed.
3.	Score 3 points if correct choice is circled, otherwise 0.
4.	Score 6 points if statement matches the one given in class. Deduct 1 point if the warning about finite s.d. is missing, half a point if the mean of the sampling distribution is not indicated in some way to be , and another half point if the s.d. of the sampling distribution is not indicated in some way to be . Deduct 2 points if the words “sampling distribution of ” or “sampling distribution of the sample mean” are missing. Deduct 4 points for failing to state that the sampling distribution approaches normality as .
5.	Score 1 point per blank, 3 points in all. Deduct half a point for each spelling error.
6, 7.	Score 3 points for properly describing the need for n to be about 30 or greater if population distribution is nonnormal, 3 more points for the warning about the need for finite s.d.
8.	Score 5 points if explanation is coherent. Deduct 1 point for not include the word “parameter” somewhere in the explanation, half a point for each misspelling.
9.	Score 3 points for sketch with at least 2 x-values marked (preferably 3 or 4, but only 2 are required). Score 4 points for proper computation of (correct notation for , formula, plug-ins, answer). Score 4 points for providing justification based on n > 30 (no credit for using the proportion rules of thumb). Score 4 points for answer, deducting 1 point if fewer than 3 decimal places were provided. Deduct 1 point if “normalcdf” or any other calculator-type notation occurs anywhere, unless it was crossed out. Total possible: 15 points.
10.	Score 3 points for sketch with at least 2 x-values marked (preferably 3 or 4, but only 2 are required). Score 4 points for proper computation of (correct notation for , formula, plug-ins, answer). Score 6 points for stating and checking the rules of thumb (1 point for each statement + 1 point for each plug-in and written verification). No credit for saying n > 30. Score 4 points for answer, deducting 1 point if fewer than 3 decimal places were provided. Total possible: 17 points.
11.	Score 1.5 if the word “binomial” appears somewhere in the response, another 1.5 for writing the expression or something similar. Score 3 points for answer, deducting 1 point if fewer than 3 decimal places were provided. Deduct 1 point if “binomcdf” or any other calculator-type notation occurs anywhere, unless it was crossed out. Total possible: 6 points.
	Points possible for entire test (including battery bonus) = 101. Do not count the metaknowledge bonus when computing your estimated score, but do count the battery bonus if you earned it.