Q1
Define the following term
s
.
a.
Observational study
b.
Designed experiment
a.
C
hoose the correct answer below.
A
.
In an observational study, researchers impose treatments and controls and then observe characteristics and take measurements.
B
.
In an observational study, researchers simply observe characteristics and take measurements, as in a sample survey.
C.
In an observational study, researchers look at all the members of the group being studied.
Q2
Data from a sample of citizens of a certain country yielded the following estimates of average TV viewing time per month for all the citizens. The times are in hours and minutes. (
NA
, not available)
Viewing method |
May 200 8 |
May 2007 |
Change (%) |
Watching TV in the home |
127:31 |
121:41 |
5 |
Watching timeshifted TV |
5:48 |
3:46 |
54 |
Using the Internet |
26:47 |
24:44 |
8 |
Watching video on Internet |
2:14 |
NA |
Is the study descriptive or inferential?
A.
Inferential, because the statistics are used to make an inference about the population
B.
Descriptive, because the statistics are used to make an inference about the population
C.
Descriptive, because the statistics are used to describe the sample
D.
Inferential, because the statistics are used to describe the sample
Q3
Is the following study descriptive or inferential?
n a statistical magazine, average professional athletes’ salaries in three sports were compiled and compared for the years 1993 and 2003.
Is the study descriptive or inferential?
A.
Inferential, because the statistics are a summary of the average salaries of professional athletes in three sports
B.
Descriptive, because the statistics are a summary of the average salaries of professional athletes in three sports
C.
Inferential, because the statistics are used to make an estimate of the average salaries of all professional athletes
D.
Descriptive, because the statistics are used to make an estimate of the average salaries of all professional athletes
. |
Average salary ($1000) |
||
Sport |
1993 |
2003 |
A |
1,083 |
2,356 |
B |
1,363 |
3,933 |
C |
627 |
1,257 |
Q4
A recent article postulated that support for a certain scientist’s theories increases with level of education. The table shown to the right provides percentages of a certain country’s adults, by educational level, who believe that evolution is a scientific theory well supported by evidence. Complete parts a and b. Education |
Percentage |
65% |
52% |
32% |
20% |
Do you think that this study is descriptive or inferential? Explain your answer. |
A.
The study is inferential because a sample was taken.
B.
The study is inferential because a sample was used to make an inference about the population.
C.
The study is descriptive because it is a summary of the opinions of a sample of adults.
D.
The study is descriptive because it involves percentages.
s
A nationwide survey of 1000 adults found that
50%
of respondents favored a plan to break up the 12 megabanks, which then controlled about
69%
of the banking industry. Complete parts (a) and (b) below.
Identify the population and sample for this study. Choose the correct answer below.
A.
The population is
all adults in the country. The sample is those adults who favored breaking up the megabanks.
B.
The population is all adults in the country. The sample is the 1000 adults surveyed.
C.
The population is all adults in the country who favored breaking up the megabanks. The sample is the 1000 adults surveyed.
D.
The population is the 1000 adults surveyed. The sample is those adults who favored breaking up the megabanks.
Q6
Determine whether the study depicts an observational study or an experiment.
Fifty patients with colon cancer divided into two groups. One group receives an experimental drug to fight cancer, the other a placebo. After one year , the spread of the cancer is measured
Does the description correspond to an observational study or an experiment?
A- The study is an observational study because the researches control one variable to determine the effect on the response variable.
B- The study is an observational study because the study examines individuals in a sample, but does not try to influence the response variable
C- The study is experiment because the study examines individuals in a sample, but does not try to influence the variable of interest
D- The study is experiment because the researchers control one variable to determine the effect one the response variable
Q 7
Determine whether the study depicts an observational study or a designed experiment.
A poll is conducted in which 501 elementary school students are asked about how much they read each week
Is the study an observational study or a designed experiment?
Observational study
Designed experiment
Q8
A report stated that 65% of people between the ages of 21 and 29 favor foregin military intervention “ the percentage of 65% was computed from sample data
Complete parts (a) through (d) below.
a. Identify the population under consideration.
The population is
Q9
In sampling, explain why obtaining a representative sample is important.
Why is obtaining a representative sample important?
A.
The sample must be representative in order to be used as part of a designed experiment rather than an observational study.
B.
The sample must be representative in order to use inferential statistics to draw conclusions about the entire population.
C.
The sample must be representative in order to establish causation rather than only reveal association.
D.
The sample must be representative in order to be considered a simple random sample.
Q 10
What is the acronym used for simple random sampling without replacement?
The acronym ………………. is used for simple random sampling without replacement.
SRS
SRSWR
RSR
SRSWOR
Q11
A class has 50 students. Use the firstfirst row of digits in the random number table below to select a simple random sample of three students. If the students are numbered 01 to 50, what are the numbers of the three students selected?
Line/ Column
(1)
(2)
(3)
(4)
1
54105
03042
58811
41590
2
06053
27367
11152
46533
3
74943
78866
62684
23574
Q 12
Five state officials are listed to the right.
a- List the 10 possible samples ( without replacement) of size 3 that can be obtained from the population of five officials
b- If simple random procedure is used to obtain a sample of three officials, what are the chances that it is the first smaple on your list in part(a)? the second sample? The tenth sample?
a. List all 10 possible samples (without replacement) of size 3. Use the letter abbreviation for each official
s
(Use a comma to separate answers as needed.)