Stats Final

Question 1

The value of a parameter may change as the sample value changes.

Answer

true

Question 2

A type of research inference involves using a statistic to estimate a parameter

Answer

true

Question 3

The value of a statistic is fixed

Answer

true

Question 4

In theory, the value of a continuous variable may take any value in some interval of numbers

Answer

true

Question 5

A random sample guarantees a representative sample

Answer

true

Question 6

For an experiment, a researcher manipulates conditions under which observations are made

Answer

true

Question 7

A random sample maximizes the probability of obtaining a representative sample

Answer

true

Question 8

The science of statistics can be used to prove anything a researcher would like to prove

Answer

true

Question 9

For an observational study, a researcher merely records values of the dependent variable. That is, the researcher does not manipulate conditions under which observations are made.

Answer

true

Question 10

The value of a statistic may change as the sample changes

Answer

true

Question 11

Boxplots are a graphical display of the 5-number summary

Answer

true

Question 12

If two events A and B are disjoint, then A ∩ B = {0}

Answer

true

Question 13

For the data set consisting of the four numbers -3, -2, -2, -5, a valid measure of spread for all the data will be <0

Answer

true

Question 14

The sample mean x̄, is always the balance point of the relative frequency histogram for the data

Answer

true

Question 15

The sample median x̃, is always the balance point of the relative frequency histogram of the data

Answer

true

Question 16

A positive correlation between two quantitative variables X and Y implies that as one increases the other tends to decrease

Answer

true

Question 17

A positive correlation between two quantitative variables X and Y implies that as one increases, the other tends to increase

Answer

true

Question 18

If two events are disjoint, then A U B = ϕ

Answer

true

Question 19

The probability of the sample space is less than 1 when the probability of all the events contained in the sample space is less than 1.

Answer

true

Question 20

The Standard Normal Curve is always symmetric around 0

Answer

true

Question 21

When two events A and B are independent, the 
 P (A and B) = P (A) X P (B)

Answer

true

Question 22

When Z~ N (0, 1), then P (Z ≤ -1.34) = P (Z > 1.34)

Answer

true

Question 23

When X~ N ( μ, σ), then x̄~ N ( μ,  σ/√n)

Answer

true

Question 24

When two events A and B are independent, then
  P (A ∩ B) = P (A) + P (B)

Answer

true

Question 25

The Rule of Thumb for independence when drawing without replacement from a population states when the sample size is ≤ 5% of the population size, we can assume the draws are independent

Answer

true

Question 26

H0: μ = 0 is only rejected when the p-value is > 0.05

Answer

true

Question 27

H1: μ ≠ 0 is only accepted when the p-value > 0.05.

Answer

true

Question 28

Suppose a 95% confidence interval for a population mean μ is given by (-17.32, 13.1). Then there is a 5% chance that μ will fall outside this interval.

Answer

true

Question 29

Suppose a 95% confidence interval for a population mean μ is given by (-17.32, 13.1). Then there is a 95% chance that μ will fall in this interval.

Answer

true

Question 30

If the sampled population is normal, then the sampling distribution of x̄ is normal when based on a random sample.

Answer

true

Question 31

The number of new projects started each month at a cancer research center for the last nine months are:
                             0, 6, 10, 10, 12, 12, 16, 30
The sample median x̃ for the data is given by:

Accepted Answer

10

Answer

11

Answer

12

Answer

10.5

Question 32

The number of new projects started each month at a cancer research center for the last nine months are:
                             0, 6, 10, 10, 12, 12, 16, 30
The IQR for the above data is:

Accepted Answer

6

Answer

8

Answer

7

Answer

14

Question 33

The number of new projects started each month at a cancer research center for the last nine months are:
                             0, 6, 10, 10, 12, 12, 16, 30
Based on our Rule of Thumb for outliers, the following holds:

Accepted Answer

The maximum value is an outlier

Answer

There are no outliers

Answer

The minimum value is an outlier

Answer

The median value is an outlier

Question 34

Which of the following sets of numbers has the smallest possible variance?

Accepted Answer

-12, -12, -12, -12

Answer

7, 8, 9, 10

Answer

0, 0, 10, 10

Answer

20, 23, 23, 30

Question 35

The variance of 11 measurements of newborn height's (measured in inches) is computed to be 4 with a sample mean height of 20. 
The units for the sample mean are:

Accepted Answer

inches

Answer

square root inches

Answer

inches squared

Answer

no units, mean never has units

Question 36

The variance of 11 measurements of newborn height's (measured in inches) is computed to be 4 with a sample mean height of 20. 
The standard deviation of these measurements is:

Accepted Answer

2

Answer

16

Answer

4

Answer

8

Question 37

The units for the variance are

Accepted Answer

inches squared

Answer

inches

Answer

square root inches

Answer

no units, variance never has units

Question 38

Volunteers for a research study were divided into three groups. Group 1 listened to Western religious music, Group 2 listened to Western rock music, and Group 3 listened to Chinese religious music. The blood pressure of each volunteer was measured before and after listening to the music, and the change in blood pressure was recorded. The scatterplot is given below
What does the scatterplot suggest about the correlation between change in blood pressure and type of music?

Accepted Answer

None of the above

Answer

It is strongly negative

Answer

It is strongly positive

Answer

It is first strongly negative and then strongly positive

Question 39

Volunteers for a research study were divided into three groups. Group 1 listened to Western religious music, Group 2 listened to Western rock music, and Group 3 listened to Chinese religious music. The blood pressure of each volunteer was measured before and after listening to the music, and the change in blood pressure was recorded. The scatterplot is given below
What could we do to explore the relationship between type of music and change in blood pressure?

Accepted Answer

Make side-by-side boxplots of the change in blood pressure, with a separate boxplot for each group

Answer

See if blood pressure decreases as type of music increases by examining a scatterplot

Answer

Make a histogram of the change in blood pressure for all of the volunteers

Answer

Do all of the above

Question 40

Events A, B, and C represent all possible outcomes of an experiment. That is, the sample space is given by S= {A, B, C}.
Which of the following does not have to be true?

Accepted Answer

P(A) = P(B) = P(C) = 1/3

Answer

0 ≤ P(A) ≤1
0 ≤ P(B) ≤ 1
0 ≤ P(C) ≤ 1

Answer

P ({A, B, C}) =1

Answer

P(A) + P(B) + P(C) =1

Question 41

A fair coin is tossed two times in succession and the following events are defined:
  A: {Observes at least one head}
  B: {Observe exactly two heads}
  C: {Observe exactly one head}
The sample space for this experiment is given by:

Accepted Answer

{HH, HT, TH, TT}

Answer

{H, T}

Answer

{HH, TT}

Answer

{H-T}

Question 42

A fair coin is tossed two times in succession and the following events are defined:
  A: {Observes at least one head}
  B: {Observe exactly two heads}
  C: {Observe exactly one head}
Using classical assignment of probability, the P(C) is:

Accepted Answer

2/4

Answer

1/4

Answer

3/4

Answer

1

Question 43

Three experimental groups representing fitness levels for a random sample of U.S. men aged 35-45 were determined. The following chart represents the boxplots for the variable resting heart rate:
Which experimental group has the largest IQR?

Accepted Answer

Experimental group 0

Answer

Experimental group 1

Answer

Experimental group 2

Answer

Unable to determine using boxplots

Question 44

Which of the following recorded variables is continuous?

Accepted Answer

Age, in years, of a randomly selected U.S. college student

Answer

Town of residence of a randomly selected college student

Answer

Number of people, both adults and children, living in a randomly selected U.S. household

Answer

Total household income (number of dollars per year), before taxes, in 2010 of a randomly selected U.S. household

Question 45

Which of the following recorded variables is categorical?

Accepted Answer

Size of town of residence, measured as "small" for sizes ≤ 70,000; or "large" for sizes > 70,000 for a randomly selected U.S. college student

Answer

Number of residents per household working outside the home for a randomly selected U.S. household

Answer

The number of residents for a randomly selected U.S household

Answer

Age, in years, of a randomly selected U.S. college student

Question 46

Which of these variables is categorical?

Accepted Answer

Whether randomly selected competitors in a running contest win or lose

Answer

The race time (in minutes) of a randomly selected participant in the 2013 New York City marathon

Answer

The number of animals within a randomly selected geographical area

Answer

The total number of contests won by randomly selected competitors for the year 2012

Question 47

Does ginkgo biloba enhance memory? In a study to find out, 100 adult subjects who take ginkgo biloba once a day were randomly selected and 100 adults who do not take ginkgo biloba were randomly selected. Each group was given a memory test. The average score for the ginkgo biloba group was 82.78 and for the no-ginkgo group the average score was 73.46
The population(s) of interest are:

Accepted Answer

All adults who take ginkgo biloba once a day; all adults who do not take ginkgo biloba

Answer

All adults

Answer

All adults who take ginkgo biloba once a day

Answer

none of the above

Question 48

Does ginkgo biloba enhance memory? In a study to find out, 100 adult subjects who take ginkgo biloba once a day were randomly selected and 100 adults who do not take ginkgo biloba were randomly selected. Each group was given a memory test. The average score for the ginkgo biloba group was 82.78 and for the no-ginkgo group the average score was 73.46
The parameters of interest for this study are:

Accepted Answer

the average test score for all adults who take ginkgo biloba and for all adults who do not take ginkgo biloba

Answer

Whether a person take ginkgo biloba or not

Answer

the memory test scores

Answer

the percentage of adults who take ginkgo biloba and the percentage of adults who do not take ginkgo biloba

Question 49

Does ginkgo biloba enhance memory? In a study to find out, 100 adult subjects who take ginkgo biloba once a day were randomly selected and 100 adults who do not take ginkgo biloba were randomly selected. Each group was given a memory test. The average score for the ginkgo biloba group was 82.78 and for the no-ginkgo group the average score was 73.46
The dependent variable for this study is given by:

Accepted Answer

the memory test scores

Answer

whether a person take ginkgo biloba or not

Answer

the average test scores for all adults who take ginkgo biloba and for all adults who do not take ginkgo biloba

Answer

the percentage of adults who take ginkgo biloba and the percentage of adults who do not take ginkgo biloba

Question 50

Does ginkgo biloba enhance memory? In a study to find out, 100 adult subjects who take ginkgo biloba once a day were randomly selected and 100 adults who do not take ginkgo biloba were randomly selected. Each group was given a memory test. The average score for the ginkgo biloba group was 82.78 and for the no-ginkgo group the average score was 73.46
The statistics calculated for this study are:

Accepted Answer

the sample averages 82.78 and 73.46

Answer

the average test scores for all adults who take ginkgo biloba and for all adults who don't take ginkgo biloba

Answer

the percentage of adults who take ginkgo biloba and the percentage of adults who do not take ginkgo biloba

Answer

none of the above

Question 51

Does ginkgo biloba enhance memory? In a study to find out, 100 adult subjects who take ginkgo biloba once a day were randomly selected and 100 adults who do not take ginkgo biloba were randomly selected. Each group was given a memory test. The average score for the ginkgo biloba group was 82.78 and for the no-ginkgo group the average score was 73.46
Is the claim "ginkgo biloba causes memory improvement" supported by this study?

Accepted Answer

No, because this is an observational study with possible confounding factors, such as genetics

Answer

Yes, because random samples were obtained and the average scores for the no-ginkgo group were lower

Answer

No, because memory test scores can only be recorded as a categorical variable

Answer

Yes, because there is evidence that the average memory test score for the population of ginkgo taking adults is higher than the average memory test score for the population of no-ginkgo taking adults

Question 52

The Gallup survey organization obtained a random sample of 2,527 U.S. citizens. The proportion in the sample who favored a constitutional amendment that would define marriage as being between a man and a woman was 1289/2527 = 51%
The population of interest consists of:

Accepted Answer

All U.S. citizens

Answer

All of the 2527 citizens sampled

Answer

All U.S. college students

Answer

All U.S. citizens who favor the amendment

Question 53

The Gallup survey organization obtained a random sample of 2,527 U.S. citizens. The proportion in the sample who favored a constitutional amendment that would define marriage as being between a man and a woman was 1289/2527 = 51%
The percentage of the 2527 citizens who favor the amendment is an example of:

Accepted Answer

a statistic

Answer

parameter value

Answer

census with respect to amendment

Answer

qualitative, continuous variable

Question 54

The Gallup survey organization obtained a random sample of 2,527 U.S. citizens. The proportion in the sample who favored a constitutional amendment that would define marriage as being between a man and a woman was 1289/2527 = 51%
The dependent variable is:

Accepted Answer

a categorical variable

Answer

a discrete quantitative variable

Answer

a continuous quantitative variable

Answer

a discrete categorical variable

Question 55

A study was conducted to determine the effect of a new low-density lipoprotein (LDL) cholesterol lowering drug compared to the currently prescribed drug. 5000 U.S. adults aged 45-65 with "high" LDL cholesterol (> 130 milligrams per deciliter (mg/dL)) were randomly selected. 2500 of the adults were randomly assigned to the new drug group and 2500 of the adults were randomly assigned to the control (currently prescribed) drug group. At the end of the 1-year study period, the average LDL cholesterol level for the 2500 patients in the new drug group was 112 mg/dL and the average LDL cholesterol level for the control drug group was 125 mg/dL.
What are the population(s) of interest for this study?

Accepted Answer

All U.S adults age 45-65 with high LDL cholesterol who take the new drug and all U.S. adults age 45-65 with high LDL cholesterol who take the control drug

Answer

All U.S. adults age 45-65

Answer

All U.S. adults age 45-65 with high LDL cholesterol and all U.S. adults age 45-65 with normal LDL cholesterol

Answer

All U.S. adults with high LDL cholesterol

Question 56

A study was conducted to determine the effect of a new low-density lipoprotein (LDL) cholesterol lowering drug compared to the currently prescribed drug. 5000 U.S. adults aged 45-65 with "high" LDL cholesterol (> 130 milligrams per deciliter (mg/dL)) were randomly selected. 2500 of the adults were randomly assigned to the new drug group and 2500 of the adults were randomly assigned to the control (currently prescribed) drug group. At the end of the 1-year study period, the average LDL cholesterol level for the 2500 patients in the new drug group was 112 mg/dL and the average LDL cholesterol level for the control drug group was 125 mg/dL.
What is the dependent variable?

Accepted Answer

LDL cholesterol after 1-year, measure in mg/dL

Answer

Drug, measured as taking new drug or control drug

Answer

age, measured in years

Answer

LDL cholesterol > 130 mg/dL

Question 57

A study was conducted to determine the effect of a new low-density lipoprotein (LDL) cholesterol lowering drug compared to the currently prescribed drug. 5000 U.S. adults aged 45-65 with "high" LDL cholesterol (> 130 milligrams per deciliter (mg/dL)) were randomly selected. 2500 of the adults were randomly assigned to the new drug group and 2500 of the adults were randomly assigned to the control (currently prescribed) drug group. At the end of the 1-year study period, the average LDL cholesterol level for the 2500 patients in the new drug group was 112 mg/dL and the average LDL cholesterol level for the control drug group was 125 mg/dL.
What type of variable is the dependent variable?

Accepted Answer

A quantitative, continuous variable

Answer

A quantitative, discrete variabel

Answer

A categorical, discrete variable

Answer

A categorical, continuous variable

Question 58

A study was conducted to determine the effect of a new low-density lipoprotein (LDL) cholesterol lowering drug compared to the currently prescribed drug. 5000 U.S. adults aged 45-65 with "high" LDL cholesterol (> 130 milligrams per deciliter (mg/dL)) were randomly selected. 2500 of the adults were randomly assigned to the new drug group and 2500 of the adults were randomly assigned to the control (currently prescribed) drug group. At the end of the 1-year study period, the average LDL cholesterol level for the 2500 patients in the new drug group was 112 mg/dL and the average LDL cholesterol level for the control drug group was 125 mg/dL.
What type of variable is the independent variable drug?

Accepted Answer

A categorical variable

Answer

A quantitative, discrete variable

Answer

A quantitative, continuous variable

Answer

A categorical, discrete variable

Question 59

A study was conducted to determine the effect of a new low-density lipoprotein (LDL) cholesterol lowering drug compared to the currently prescribed drug. 5000 U.S. adults aged 45-65 with "high" LDL cholesterol (> 130 milligrams per deciliter (mg/dL)) were randomly selected. 2500 of the adults were randomly assigned to the new drug group and 2500 of the adults were randomly assigned to the control (currently prescribed) drug group. At the end of the 1-year study period, the average LDL cholesterol level for the 2500 patients in the new drug group was 112 mg/dL and the average LDL cholesterol level for the control drug group was 125 mg/dL.
The statistics calculated for this study are:

Accepted Answer

The average LDL cholesterol levels given by 112 mg/dL and 125 mg/dL

Answer

The average LDL cholesterol levels for both the high and normal populations

Answer

The average LDL cholesterol level for all U.S. adults

Answer

Percent with "high" cholesterol for both the 2500 patients prescribed the new drug and the 2500 patients prescribed the control drug

Question 60

A study was conducted to determine the effect of a new low-density lipoprotein (LDL) cholesterol lowering drug compared to the currently prescribed drug. 5000 U.S. adults aged 45-65 with "high" LDL cholesterol (> 130 milligrams per deciliter (mg/dL)) were randomly selected. 2500 of the adults were randomly assigned to the new drug group and 2500 of the adults were randomly assigned to the control (currently prescribed) drug group. At the end of the 1-year study period, the average LDL cholesterol level for the 2500 patients in the new drug group was 112 mg/dL and the average LDL cholesterol level for the control drug group was 125 mg/dL.
The parameters of interest in this study are:

Accepted Answer

The average LDL cholesterol levels for both the new drug and the control drug populations after one year of taking the respective drug

Answer

The average LDL cholesterol levels for both the high and normal populations

Answer

The average LDL cholesterol levels for all U.S. adults

Answer

Percent with "high" cholesterol in the population of adults age 45-65

Question 61

A study was conducted to determine the effect of a new low-density lipoprotein (LDL) cholesterol lowering drug compared to the currently prescribed drug. 5000 U.S. adults aged 45-65 with "high" LDL cholesterol (> 130 milligrams per deciliter (mg/dL)) were randomly selected. 2500 of the adults were randomly assigned to the new drug group and 2500 of the adults were randomly assigned to the control (currently prescribed) drug group. At the end of the 1-year study period, the average LDL cholesterol level for the 2500 patients in the new drug group was 112 mg/dL and the average LDL cholesterol level for the control drug group was 125 mg/dL.
The research inference of interest is given by:

Accepted Answer

The new drug sample average LDL cholesterol < the control drug sample LDL cholesterol, thus estimate the new drug population average LDL cholesterol < the control drug population LDL cholesterol

Answer

The average LDL cholesterol is lower when the new drug is administered

Answer

The sample average LDL cholesterol < 130, thus estimate the population LDL cholesterol < 130

Answer

The new drug is effective for lowering LDL cholesterol

Question 62

A study was conducted to determine the effect of a new low-density lipoprotein (LDL) cholesterol lowering drug compared to the currently prescribed drug. 5000 U.S. adults aged 45-65 with "high" LDL cholesterol (> 130 milligrams per deciliter (mg/dL)) were randomly selected. 2500 of the adults were randomly assigned to the new drug group and 2500 of the adults were randomly assigned to the control (currently prescribed) drug group. At the end of the 1-year study period, the average LDL cholesterol level for the 2500 patients in the new drug group was 112 mg/dL and the average LDL cholesterol level for the control drug group was 125 mg/dL.
The design of this study is given by:

Accepted Answer

An experiment with random assignment to groups

Answer

An experiment without random assignment

Answer

An observational study without random assignment

Answer

An observational study with random assignment to groups

Question 63

The legal profession conducted a study to determine the percentage of cardiologists who had been sued for malpractice in the last five years. The sample was randomly chosen from a national directory of doctors. 
What is the dependent variable of interest in this study?

Accepted Answer

The responses: have been sued/have not been sued for malpractice in the last five years

Answer

The doctor's area of expertise

Answer

The number of doctors who are cardiologists

Answer

All cardiologists in the directory

Question 64

Ignoring twins and other multiple births, assume babies born at a hospital are independent events with the probability that a baby is a boy and the probability that a baby is a girl both equal to 0.5
What is the probability that the next two babies are of the same sex?

Accepted Answer

0.50

Answer

0.25

Answer

0.75

Answer

1.0

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