Questions:
Q1
Define the following terms.
a. Observational study b. Designed experiment
a. Choose 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 2008
|
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
|
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?
In 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
|
Q.4
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
Postgraduate education ?65%
College graduate ?52%
Some college education 32%
High school or less 20%
Q.5
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.
Q.6
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.
Q.7
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.8
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
Q.9
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
Q.10
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 han an observational study.
B.The sample must be representative in order to use inferential statistics to draw conclusions about he 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.11
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
Q.12
A class has 50 students. Use the firstfirstrow 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