Quiz 2
Mathematics 1040–2, Summer 2008
Name:
You have 20 minutes for this quiz.
1. (5 points) Does using a cell phone whil driving make an accident more
likely? Researchers compared telephone company and police records to
find 699 people who had cell phones and were also involved in auto accidents. Using phone-billing records, they compared cell-phone use in the
period of the accident with cell-phone use the same period on a previous day. Result: The risk of an accident was 4 times higher when a cell
phone was used.The researchers also recorded the manufacturer of each
subject’s cell phone (Motorola, Nokia, etc.). This variable is (circle the
most appropriate answer):
(a) Categorical;
(b) quantitative;
(c) response;
(d) invalid.
2. (5 points) You have data on returns on common stocks for all years since
1945. To show clearly how returns have changed over time, your best
choice of graph is (circle the most appropriate answer):
(a) A bar graph;
(b) a line graph;
(c) a pie chart;
(d) a histogram;
(e) a scatterplot.
3. (10 points total; 5 each) Here is a table of the undergraduate enrollment
at a large state university, broken down according to class:
Class
Freshman
Sophomore
Junior
Senior
Non-degree
Total
Student count
8,248
8,073
7,001
6,904
535
30,761
Percent of students
26.8%
26.2%
22.8%
22.4%
1.7%
100%
(a) To make a correct graph of the distribution of students by class, you
could use (circle the most appropriate answer):
i.
ii.
iii.
iv.
v.
A bar graph;
a pie chart;
a line graph;
all of (i), (ii), and (iii);
(i) or (ii), but not (iii).
(b) The percents of students in the five classifications should add to
100%. In fact, they add to only 99.9%. The reason is that (circle
the most appropriate answer):
i. There must be an arithmetic mistake;
ii. the percents are not exact, because they are rounded to one decimal place;
iii. some students must be left out, so the total should be less than
100%;
iv. this is an example of a biased measurement.
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