STATISTICS
Name____________________
Review Quiz
Period______
Answers
1. Suppose that if you make an “A” in statistics class, your parents have promised to buy you a new car. You decide to do some
preliminary research about the latest model cars. For each car that interests you, you record whether it is automatic or manual,
its average highway gas mileage, and its cost.
(a) What are the individuals in this study? Latest model cars
(b) What variables are you recording? For each variable, state if it categorical or quantitative.
Automatic or manual-categorical
Average highway gas mileage-quantitative
Cost-quantitative
2. Many people suffer from migraine headaches. A variety of over-the-counter medicines are available for migraine sufferers. A
doctor wants to determine which of two available drugs is more effective in reducing the pain experienced by patients with
migraine headaches.
(a) Would it be best for him to collect data on this question using an experimental study, observational study, or census? Justify
your choice.
Experimental study-an observational study does not prove causation, so experimental would be better to show cause and
effect. We should test the 2 drugs and a placebo as well.
(b) Are the volunteers who sign up for the study considered the population or the sample?
sample
3. In 1995, the Gallup Poll asked a sample of 620 U.S. adults whether their support of baseball had been affected by a recent
players' strike; 248 people, or 40%, said “Yes."
(a) Identify the population of interest in this setting.
All U.S. adults
(b) Identify the sample in this setting.
620 U.S. adults
(c) Is the number 40% a parameter or a statistic?
statistic
(d) The poll reported a margin of error of 4%. Could we be confident in saying that less than ½ of all US adults agreed that their
support of baseball had been affected by the recent players’ strike? Why?
Yes, even if 40% is wrong by 4% in the higher direction, it is still under 50%.
(e) Suppose another poll was asking people the same question but instead of using Gallup’s dialing methods, it asks the first 600
people going into a baseball stadium. What problems might this poll have?
Selection bias-people attending a baseball game are more likely already baseball fans and will have a stronger opinion
relating to baseball than your average American may have.
4. Which is better in general – taking one measurement, or taking the average of several measurements? Explain.
Taking the average of several measurements is better since having a larger sample gives an average that is closer to the
actual measurement. If you are wrong on one measurement, then you are just stuck with a wrong measurement, but if you
measure several times, then you will get closer and closer with the average of the measurements.
5. A student at a large university wants to study the responses that students receive when calling an academic department for
information. She wants to select an SRS of 6 departments from the following list for her study.
01 Agronomy
08 Art and Design
15 Audiology
22 Biochemistry
02 Biology
09 Chemistry
16 Communication
23 Computer Science
03 Consumer Science 10 Education
17 Electrical Eng
24 English
04 Foreign Languages 11 History
18 Horticulture
25 Industrial Eng
05 Management
12 Mathematics
19 Nursing
26 Pharmacology
06 Philosophy
13 Physics
20 Political Science
27 Psychology
07 Sociology
14 Statistics
21 Veterinary Anatomy
Describe how to go about obtaining an SRS of 6 departments using the partial random digits table below. Be very specific so she
can follow your instructions with ease. Mark directly on the table to show your process clearly and list out the 6 chosen
departments.
27816 78416 18329 21337 35213 37741 04312 68508
08421
44753
77377
28744
75592
08563
79140
92454
Number the departments 01 through 27. Start at the beginning of the given table and select the department that
corresponds with the 2 digit number given, in order. If a number is higher than 27 or if it repeats, just skip it.
27 Psychology, 16 Communication, 18 Horticulture, 13 Physics, 21 Veterinary Anatomy, 04 Foreign Language
7. The school nurse would like to know the average height and weight of students in each of the four grade levels. State what
type of sampling method (stratified, simple random sample, or systematic) is described below.
SRS
stratified
systematic
(a) Using a random number table and a list of all students, take a random sample of 40 students from all
the students in the school.
(b) Separate the students by grade level. Using a random number table and the four lists of students,
take a random sample of 10 students from each grade level.
(c) Using a list of all students in the school, choose a random starting point, and take every 30th student
from that point in the list.