Download Stat 200. Exam 1 - Radford University

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Stat 200. Exam 1 (100 Points)
Directions:
Show enough work that I can understand what you did to get your answers. (For example, “I used
the command ... on my TI.”) Round all numerical answers to two decimal places (for example,
1.23). The maximum possible score is 110.
Assume the following sample of SAT scores for a certain university is representative of the
scores for incoming freshmen at that university. (You should already have the sample in a list in
your TI.)
1325 1072 982 996 872 849 785 706
669 1049 885 1367 935 980 1188 869
1006 1127 979 1034 1052 1165 1359 667
1264 727 808 955 544 1202 1051 1173
410 1148 1195 1141 1193 768 812 887
1211 1266 830 672 917 988 791 1035
688 700
1. Calculate x.
2. Calculate S.
3. x and S are best described as which of the following: population parameters, sample statistics,
sample parameters, population statistics? (Circle one.)
4. Determine the interquartile range.
5. Have your TI construct a default histogram for the data. (You need not include the histogram
here.) What boundaries did it use for the third class?
6. What is the relative frequency for the third class?
7. Determine the z-value for the score of 1168.
8. If a z-value for some student were 2.5, what would be the student’s raw score?
9. Assume that the sample is bell-shaped enough that the Empirical Rule applies. What fraction
of the students should score within approximately one standard deviation above the mean.?
10. In a similar sample of scores for 600 students, approximately how many of the students would
we expect to score within one standard deviation above the mean?
11. When CNN conducts the polls about the upcoming congressional elections, Glenn Beck will
probably jump up and down on his daily tv broadcast if they do which of the following?
(a) Ensure their samples are reasonably representative of voters who will vote in the elections.
(b) Give indications of possible sampling errors.
(c) Perform the polls so as to ensure 100% accuracy.
(d) Limit themselves to the polls in which democrats are most likely to gain seats.
(e) Use reasonably large sample sizes.
12. Which of the following sample statistics do not use the same units?
(a) mean and mode
(b) mean and standard deviations
(c) mean and variance
(d) median and standard deviation
The following table contains a frequency distribution for the number of children of our first
forty-two presidents.
Class
Boundaries
Frequencies
1
0-2
16
2
3-5
17
3
6-8
7
4
9-11
1
5
12-14
0
6
15-17
1
13. The manner in which the data represented by this table are distributed would best be classified
as which of the following: bimodal, skewed right, skewed left, bell-shaped, evenly spread?
(Circle one.)
14. Use your TI to estimate x and S to two decimal places for these grouped data.
15. Determine the relative frequency for the third class.
16. Which class is the modal class?
17. Which class is the median class?
18. This table was constructed a few years ago. If President O’Bama were added to the list, which
of the following necessarily would not change at all for this sample: the mean, the standard
deviation, the range, the MAD number? (Circle one.)
19. According to Wikipedia, there are two recorded cases in history in which a woman gave birth
to sixty-nine children each (fer real). Let’s pretend that one of these women was the wife of
one of our other presidents (they weren’t; but let’s pretend anyway). Which of the following
would change the most if her 69 children were added to the list: the mean, the median, the
mode, the basic shape? (Circle one.)
20. President Obama is currently our 44th president. He was was mildly chastised by the press for
making the following statement in his innaugural address: “Forty four Americans have now
taken the presidential oath.” His statement was, in fact, technically incorrect. Why?
(a) He didn’t count himself among the forty-four presidents.
(b) One of our presidents served two nonconsecutive terms.
(c) He thought his immediate predecessor, George W. Bush, sucked and was trying to gig him.
(d) His speech writers played a practical joke on him.
21. Which of the following presidents were not children of a previous president?
(a) Franklin Roosevelt
(b) George Bush
(c) John Adams
(d) Each of the three was a son of a previous president.
22. Which of the following could never convey any useful information in a statistical analysis?
(a) the gender of the analyst
(b) the sum of the individual deviations from the sample mean
(c) the ethnicity of the analyst
(d) the sample size
(e) the manner in which the data are distributed