question test on statistic

Question 1

Part 1
In an AOL survey of Internet​ users, this question was posted​ online: “Have you ever been hit by a computer​ virus?” Among the​ 170,063 responses,​ 63% answered​ “yes.” What term is used to describe this type of survey in which the people surveyed consist of those who chose to​ respond? What is wrong with this type of sampling​ method?

What term is used to describe this type of​ survey? Select all that appl

What is wrong with this type of sampling​ method? Select all that apply.

Answer 1

A.
The respondents are a​ self-selected sample.
B.
The respondents are a voluntary response sample.

A.
The respondents are a​ self-selected sample.
B.
The respondents are a

D.
Many people may choose not to respond to the survey.

E.
Responses may not reflect the opinions of the general population.

Question 2

.When testing a new​ treatment, what is the difference between statistical significance and practical​ significance? Can a treatment have statistical​ significance, but not practical​ significance?

Answer 2

C.
Statistical significance is achieved when the result is very unlikely to occur by chance. Practical significance is related to whether common sense suggests that the treatment makes enough of a difference to justify its use. It is possible for a treatment to have statistical​ significance, but not practical significance.

Question 3

Determine whether the given source has the potential to create a bias in a statistical study.
A data set includes brain volumes from 10 pairs of monozygotic​ (identical) twins. The data were collected by researchers at Harvard​ University, Massachusetts General​ Hospital, Dartmouth​ College, and the University of California at Davis

Answer 3

C.
There does not appear to be a potential to create a bias. The organizations collecting the data are reputable.

Question 4

Determine whether the given source has the potential to create a bias in a statistical study.
An article in Journal of Nutrition​ (Vol. 130, No.​ 8) noted that chocolate is rich in flavonoids. The article notes​ “regular consumption of foods rich in flavonoids may reduce the risk of coronary heart​ disease.” The study received funding from​ Mars, Inc., the candy​ company, and the Chocolate Manufacturers Association.

Answer 4

c.
The researchers may have been more inclined to provide favorable results because funding was provided by a party with a definite interest. The bias could have been avoided if the researchers were not paid by the candy company and the chocolate manufacturers.

Question 5

Determine whether the sampling method described below appears to be sound or is flawed.
In a survey of ​subjects, the following question was posted on a​ newspaper’s ​website: “In your​ view, are nuclear plants​ safe?” The survey subjects were Internet users who chose to respond to the question posted on the electronic edition of the newspaper.

Answer 5

A.
It is flawed because it is a voluntary response sample.

Question 6

Determine whether the results below appear to have statistical​ significance, and also determine whether the results have practical significance.
In a study of a weight loss​ program, subjects lost an average of lbs. It is found that there is about a ​% chance of getting such results with a diet that has no effect.

Does the weight loss program have practical​ significance?

Answer 6

D.
​No, the program is not statistically significant because the results are likely to occur by chance.

C.
​Yes, the program is practically significant because the amount of lo

Question 7

Determine whether the results appear to have statistical​ significance, and also determine whether the results appear to have practical significance.
One of a​ botanist’s hybridization experiments with peas yielded 500 offspring with 128 of those peas​ (or 26​%) having yellow pods. According to genetic​ theory, 25% of the offspring peas should have yellow pods.

Answer 7

Does the result have statistical​ significance?
According to genetic​ theory,
  
(125)* of the (500)* peas would have yellow pods. The difference between the actual number of peas with yellow pods and the expected number of peas with yellow pods is
  (3 )​pea(s). This difference (does not appear)
to be statistically significant.
​(Type whole​ numbers.)
Part 2
Does the result have practical​ significance?
This difference
(does not appear)*
to have practical​ significance, because the difference between the actual number of peas with yellow pods and the expected number of peas with yellow pods is
(very small)*
compared to the actual number of peas with yellow pods.

Question 8

Determine whether the underlined number is a statistic or a parameter.
In a study of all 3849 seniors at a college, it is found that 50% own a television.

Answer 8

Parameter because the value is a numerical measurement describing a characteristic of a population.

Question 9

Determine whether the data described below are qualitative or quantitative and explain why.

Question 10

Determine whether the data described below are qualitative or quantitative and explain why.
The preferred hands of an experiment’s participants.

Answer 10

The data are qualitative because they don’t measure or count anything.

Question 11

State whether the data described below are discrete or continuous, and explain why.
The numbers of hotel in cities.

Answer 11

The data are discrete because the data can only take on specific values.

Question 12

Determine wether the given value is a statistic or a parameter.
A homeowner measured the voltage supplied to his home on 323 days of given year, and the average (mean) Value is 107.6 volts.

Answer 12

The given value is a statistic for the year because the data collected represent a sample.

Question 13

The sinking of the titanic on April 15, 1912, is one of the most infamous disaster in history. A population of 1503 passenger and crew died when the titanic sank approximately 400 miles south of Newfoundland, Canada. Identify whether the given value is a statistic or a parameter.

Answer 13

The value is a parameter because it describes some characteristic of a population.

Question 14

In study of a sample of babies born at hospitals in one state, it was found that the average (mean) weight at birth was 3134.2 grams. Identify whether this value is a statistic or a parameter.

Answer 14

The Value is a statistic because it describe some characteristic of a sample.

Question 15

State whether the data described below are discrete or continuos, and explain why.
The exact heights of different elephants.

Answer 15

The data are continuous because the data can take on any value in an interval.

Question 16

State whether the data described below are discrete or continuous, and explain why.
The numbers of teeth that different animal have

Answer 16

The data are discrete because the data can only on specific value.

Question 17

State whether the data described below are discrete or continuous, and explain why.
The exact length ( in centimeters) of different fish found in a lake

Answer 17

The data are continuous because the data can take on any value in an interval.

Question 18

Determine which of the four levels of measurement ( nominal, ordinal, interval, ratio) is most appropriate.

Answer 18

C. Nominal

Question 19

Determine which of the four levels of measurement ( nominal, ordinal, interval, ratio) is most appropriate for the data below.
Brands of toothpaste

Answer 19

A. The nominal level of measurement is most appropriate because the data cannot be ordered.

Question 20

Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below.
Years in which U.S. presidents were inaugurated

Answer 20

The interval level of measurement is most appropriate because the data can be ordered, differences can be found and are meaningful, and there is no natural starting zero point.

Question 21

Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below.
Course grades from A to F.

Answer 21

The ordinal level of measurement is most appropriate because the data can be ordered, but differences cannot be found or are meaningless.

Question 22

Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below.
People’s ages

Answer 22

The ratio level of measurement is most appropriate because the data can be ordered, difference (obtained by subtraction) can be found and are meaningful, and there is a natural starting zero point.

Question 23

Determine which of the for levels of measurement (nominal, ordinal, interval, ratio) is most appropriate
Ages of children: 4,5,6,7, and 8

Answer 23

Ratio

Question 24

Identify the level of measurement of the data, and explain what is wrong with the given calculation.
In surgery, the responses of respondents are identified as 100 for a “yes”, 200 for “no”, 300 for a “maybe” and 400 for anything else. The average (mean) is calculated for 525 respondents and the result is 256.1.

Answer 24

Such data are not counts or measurement of anything, so it makes no sense to compute their average (mean).

Question 25

Identify the level of measurement of the data, and explain what is wrong with the given calculation.
In a set of data, alert levels are represented as 10 for low, 20 for medium, and 30 for high. The average (mean) of the 798 alert level is 25.4.

Answer 25

The data are the (ordinal)* level of measurement.
What is wrong with the given calculation?
B. Such data should not be used for calculations such as an average (mean).

Question 26

Determine whether the given value is from a discrete or continuous data set.
When a car is randomly selected, it is found to have 2 doors.

Answer 26

A. A discrete data set because there are a finite number of possible values.

Question 27

Which of the following is NOT a level of measurement?

Answer 27

Quantitative

Question 28

Which of the following consists of discrete data?

Answer 28

Number of suitcases on a plane

Question 29

Researchers conducted a study to determine whether magnets are effective in treating back pain. Pain was measured using the visual analog​ scale, and the results given below are among the results obtained in the study. Higher scores correspond to greater pain levels. Is this study an experiment or an observational​ study? Explain.
Reduction in Pain Level After Magnet​ Treatment: n=20​,X=0.487​, s=0.957
Reduction in Pain Level After Sham​ Treatment: n​=20,X=0.438​, s=1.43

Answer 29

The study is an experiment because subjects were given treatments.

Question 30

In a​ double-blind experiment designed to test the effectiveness of a new medication as a treatment for lower back​ pain, 1643 patients were randomly assigned to one of three​ groups: (1) the 547 subjects in the placebo group were given pills containing no​ medication; (2) 550 subjects were in a group given pills with the new medication taken at regular​ intervals; (3) 546 subjects were in a group given pills with the new medication to be taken when needed for pain relief.
What does it mean to say that the experiment was​ “double-blind”?

Answer 30

D.
The subjects in the study did not know whether they were taking a placebo or the new​ medication, and those who administered the pills also did not know.

Question 31

In a study designed to test the effectiveness of a medication as a treatment for lower back​ pain, 1643 patients were randomly assigned to one of three​ groups: (1) the 547 subjects in the placebo group were given pills containing no​ medication; (2) 550 subjects were in a group given pills with the medication taken at regular​ intervals; (3) 546 subjects were in a group given pills with the medication to be taken when needed for pain relief. In what specific way was replication applied in the​ study?

Answer 31

D.
The group sample sizes are all large so the researchers could see the effects of the treatment

Question 32

Determine whether the description corresponds corresponds to an observational study or an experiment.
Research is conducted to determine if there is a relation between lung capacity and proximity to coal mines.

Answer 32

Observational study

Question 33

Identify the type of sampling used( Radom, systematic, convenience, stratified, or cluster sampling) in the situation described below.
A researcher select every 531 th social security number and surveys the corresponding person.

Answer 33

systematic sampling

Question 34

Identify the type of sampling used (random, systematic, convenience, stratified, or cluster sampling) in the situation described below.
In a poll conducted by a certain research center, 1148 adults were called after their telephone numbers were randomly generated by a computer, and 21% were able to correctly identify the attorney general.

Answer 34

Random sampling.

Question 35

Identify the type of sampling used (random, systematic, convenience, stratified, or cluster sampling) in the situation described below.
A man is selected by a making company to participate in a paid focus group. The company says that the man was selected because he was ramdomly chosen from all men in his tax bracket.
Which type of sampling did the making company use?

Answer 35

Stratified sampling

Question 36

Identify which type of sampling is used: Radom, systematic, convenience, stratified, or cluster.
To determine customer opinion of their inflight service, continental Airline randomly selected 110 flights during a certain week and surveys all passengers on the flights.

Answer 36

Cluster

Question 37

Question content area top
Part 1
Identify which of these types of sampling is​ used: random,​ systematic, convenience,​ stratified, or cluster.
A large company wants to administer a satisfaction survey to its current customers. Using their customer​ database, the company randomly selects 90 customers and asks them about their level of satisfaction with the company.

Answer 37

Random

Question 38

Identify which of these types of sampling is​ used: random,​ systematic, convenience,​ stratified, or cluster.
To determine her blood pressure , jean divides up her day into three​ parts: morning,​ afternoon, and evening. She then measures her blood pressure, at 4 randomly selected times during each part of the day.

Answer 38

Stratified

Question 39

Identify the type of sampling​ used: random,​ systematic, convenience,​ stratified, or cluster.
To estimate the percentage of defects in a recent manufacturing​ batch, a quality control manager at microsoft selects every 11th software CD that comes off the assembly line starting with the seventh until she obtains a sample of 60 software CD .

Answer 39

C.
Systematic

Question 40

Which of the following corresponds to the case when every sample of size n has the same chance of being​ chosen?

Answer 40

Simple random sample

Question 41

Question content area top
Part 1
A study is conducted to measure​ children’s growth rates without any treatment applied to the children. What best classifies this​ study?

Answer 41

Observational study

Question 42

Which sampling method subdivides the population into categories sharing similar characteristics and then selects a sample from each​ subdivision?

Answer 42

Stratified

Question 43

Which sampling method divides the population up into​ sections, randomly selects some of those​ sections, then chooses all the members from the selected sections to​ study?

Answer 43

Cluster

Question 44

Determine whether the study is an experiment or an observational​ study, and then identify a major problem with the study.
A medical researcher tested for a difference in systolic blood pressure levels between male and female students who are 12 years of age. She randomly selected four males and four females for her study

Answer 44

B.
The sample is too small.

Question 45

Identify the type of sampling used( Random, systematic, convenience, stratified, or cluster sampling) in the situation described below.
A men experienced a tax audit. The tax department claimed that the man was audited because he was randomly selected from all men in his age group.
Which type of sampling did tax department use?

Answer 45

Stratified sampling

Question 46

Identify which of these types of sampling is used: random, systematic, convenience, stratified or cluster.
A market research has partitioned al residents of certain region into categories of unemployed, employed full time, and employed part time. She is subverting 58 people from each category.

Answer 46

Stratified sampling.

Question 47

Identify which type of sampling is used: random, systematic, convenience, stratified or cluster.
A radio station asks its listeners to call in their opinion regarding the use of pesticides in residential area.

Answer 47

Convenience

Question 48

Identify the type of a derivational study (cross-sectional, retrospective, or prospective) described below.

Answer 48

A retrospective study