Deck 11: Estimation and Confidence Intervals

Question 1

A researcher estimates the 95% CI for a sample with a mean of M = 3.26 and a standard error (
)of 0.91.What is the upper confidence limit for this interval?

A)1.48
B)2.35
C)4.17
D)5.04

Answer 1

D

Question 2

A researcher estimates the 95% CI for a sample with a mean of M = 3.26 and a standard error (
)of 0.91.What is the lower confidence limit for this interval?

A)1.48
B)2.35
C)4.17
D)5.04

Answer 2

A

Question 3

The confidence interval for one sample selected from a population with a known variance is computed using a critical value for which type of test?

A)z test
B)t test
C)none
D)both A and B

Answer 3

A

Question 4

Which of the following explains why point estimation can be a useful procedure to estimate a population mean?

A)It defines the range of scores within which the population mean is likely to be contained.
B)The sample mean is equal to the population mean on average.
C)The sample mean is an unbiased estimator of the population mean.
D)both B and C

Question 5

A point estimate is typically reported with an interval estimate.Why?

A)Using only a point estimate is associated with low certainty.
B)The interval estimate gives researchers a higher level of confidence.
C)The interval estimate adds certainty to the estimate of the population mean.
D)all of the above

Question 6

A researcher concludes that stress levels are higher following a major versus a minor traffic accident (95% confidence interval [CI] 1.86-3.02).If the null hypothesis stated that there would be no difference (null hypothesis: µ = 0),then what is the effect size for this confidence interval?

A)Between 1.86% and 3.02% of the variability in stress levels can be accounted for by type of traffic accident.
B)Ratings of stress shifted more than 1.86 points in the population.
C)Ratings of stress shifted between 1.86 and 3.02 points in the population.
D)There is not enough information to answer this question.

Question 7

Which type of error is used to compute the confidence interval for one sample selected from a population with a known variance?

A)standard error
B)estimated standard error
C)estimated standard error for the difference
D)estimated standard error for the difference scores

Question 8

Which of the following best describes the goal of estimation?

A)to determine the extent to which a result is significant
B)to estimate the significance of a result
C)to narrow in on the true population mean by defining limits within which it is likely to be contained
D)both A and B

Question 9

A researcher estimates the 90% CI for a sample with a mean of M = 8.9 and a standard error (
)of 2.1.What is the confidence interval at this level of confidence?

A)90% CI 4.8,13.0
B)90% CI 5.5,12.4
C)90% CI 6.8,11.0
D)There is not enough information to answer this question.

Question 10

A researcher reports with 90% confidence that 31% to 37% of Americans believe in ghosts.What is the point estimate for this interval?

A)31%
B)34%
C)37%
D)31% to 37%

Question 11

A researcher estimates the 95% CI for a sample with a mean of M = 9.0 and a standard error (
)of 1.03.What is the confidence interval at this level of confidence?

A)95% CI 7.3,10.7
B)95% CI 8.0,10.0
C)95% CI 7.0,11.0
D)There is not enough information to answer this question.

Question 12

If the null hypothesis is outside the confidence interval,then the decision was likely to ________ using hypothesis testing.

A)reject the null hypothesis
B)retain the null hypothesis

Question 13

If the value stated by a null hypothesis is ________ the confidence interval,then the decision would have likely been to retain the null hypothesis.

A)inside
B)outside

Question 14

If the value stated by a null hypothesis is ________ the confidence interval,then the decision would likely be to reject the null hypothesis.

A)inside
B)outside

Question 15

A researcher reports that college students consume an average of 3.6 alcoholic drinks per week.What is the interval estimate in this example?

A)3.6
B)The interval estimate is not given.

Question 16

The confidence interval for samples selected from a population with an unknown variance is computed using critical values from the t table.This is true for which of the following types of samples?

A)one-sample
B)two-independent sample
C)related samples
D)all of the above

Question 17

A researcher compares the height of male executives in the U.S.to the average height of males (µ = 67 inches).He determines that the average height of male executives is 70 inches (95% confidence interval [CI] 68-72).Based on this result,what would the decision have been for a hypothesis test?

A)Reject the null hypothesis.
B)Retain the null hypothesis.
C)There is not enough information to answer this question.

Question 18

If the null hypothesis is inside the confidence interval,then the decision was likely to ________ using hypothesis testing.

A)reject the null hypothesis
B)retain the null hypothesis

Question 19

A statistical procedure in which a sample statistic is used to estimate the value of an unknown population parameter is called

A)an educated guess
B)appropriation
C)estimation
D)significance testing

Question 20

Which type of error is used to compute the confidence interval for one sample selected from a population with an unknown variance?

A)standard error
B)estimated standard error
C)estimated standard error for the difference
D)estimated standard error for the difference scores

Question 21

In a sample of 30 participants,a researcher estimates the 95% CI for a sample with a mean of
= 0.7 and an estimated standard error for the difference (
)of 0.2.What is the confidence interval at this level of confidence?

A)95% CI 0.4,1.0
B)95% CI 0.5,0.9
C)95% CI 0.3,1.1
D)There is not enough information to answer this question.

Question 22

The larger the level of confidence,the ________ precise the interval estimate.

A)more
B)less

Question 23

In a sample of 28 participants,a researcher estimates the 95% CI for a sample with a mean of M = 1.5 and an estimated standard error (
)of 0.3.What is the confidence interval at this level of confidence?

A)95% CI 1.0,2.0
B)95% CI 1.2,1.8
C)95% CI 0.9,2.1
D)There is not enough information to answer this question.

Question 24

In a sample of 18 participants,a researcher estimates the 80% CI for a sample with a mean of
= 8.8 and an estimated standard error for the difference (
)of 1.8.What is the lower confidence limit for this interval?

A)6.4
B)7.0
C)10.6
D)11.2

Question 25

In a sample of 18 participants,a researcher estimates the 80% CI for a sample with a mean of
= 8.8 and an estimated standard error for the difference (
)of 1.8.What is the upper confidence limit for this interval?

A)6.4
B)7.0
C)10.6
D)11.2

Question 26

Which type of error is used to compute the confidence interval for two related samples selected from at least one population with an unknown variance?

A)standard error
B)estimated standard error
C)estimated standard error for the difference
D)estimated standard error for the difference scores

Question 27

In a sample of 20 participants,a researcher estimates the 95% CI for a sample with a mean of M = 5.4 and an estimated standard error (
)of 1.6.What is the lower confidence limit for this interval?

A)2.1
B)3.8
C)7.0
D)8.8

Question 28

A researcher increases his level of confidence from 90% to 95%.What will happen to the precision of his estimate?

A)The estimate will be more precise.
B)The estimate will be less precise.
C)The precision of his estimate will not change.
D)It depends on the size of the population.

Question 29

In a sample of 20 participants,a researcher estimates the 95% CI for a sample with a mean of M = 5.4 and an estimated standard error (
)of 1.6.What is the upper confidence limit for this interval?

A)2.1
B)3.8
C)7.0
D)8.8

Question 30

Which of the following is a characteristic of confidence intervals?

A)The less certain an estimate,the more precise the estimate.
B)The more certain an estimate,the less precise the estimate.
C)both A and B

Question 31

In a sample of 26 participants,a researcher estimates the 90% CI for a sample with a mean of
= 0.6 and an estimated standard error for the difference scores (
)of 0.1.What is the upper confidence limit for this interval?

A)0.77
B)-0.5
C)1.7
D)2.5

Question 32

In a sample of 20 participants,a researcher estimates the 99% CI for a sample with a mean of
= 3.7 and an estimated standard error for the difference scores (
)of 0.2.What is the confidence interval at this level of confidence?

A)99% CI 3.5,3.9
B)99% CI 3.2,4.2
C)99% CI 3.1,4.3
D)There is not enough information to answer this question.

Question 33

A researcher reduces her level of confidence from 99% to 90%.What will happen to the precision of her estimate?

A)The estimate will be more precise.
B)The estimate will be less precise.
C)The precision of her estimate will not change.
D)It depends on the size of the population.

Question 34

In a sample of 17 participants,a researcher estimates the 90% CI for a sample with a mean of
= 7 and an estimated standard error for the difference scores (
)of 2.2.What is the confidence interval at this level of confidence?

A)90% CI 2.4,11.6
B)90% CI 3.2,10.8
C)90% CI 4.8,9.2
D)There is not enough information to answer this question.

Question 35

Which type of error is used to compute the confidence interval for two independent samples selected from at least one population with an unknown variance?

A)standard error
B)estimated standard error
C)estimated standard error for the difference
D)estimated standard error for the difference scores

Question 36

In a sample of 26 participants,a researcher estimates the 90% CI for a sample with a mean of
= 0.6 and an estimated standard error for the difference scores (
)of 1.1.What is the upper confidence limit for this interval?

A)-1.3
B)-0.5
C)1.7
D)2.5

Question 37

In a sample of 12 participants,a researcher estimates the 80% CI for a sample with a mean of M = 22.3 and an estimated standard error (
)of 4.7.What is the confidence interval at this level of confidence?

A)80% CI 12.1,32.5
B)80% CI 17.6,27.0
C)80% CI 15.9,28.7
D)There is not enough information to answer this question.

Question 38

In a sample of 14 participants,a researcher estimates the 90% CI for a sample with a mean of
= 10.7 and an estimated standard error for the difference (
)of 2.9.What is the confidence interval at this level of confidence?

A)90% CI 4.4,17.0
B)90% CI 5.5,15.9
C)90% CI 7.8,13.6
D)There is not enough information to answer this question.

Question 39

Which of the following words best describes certainty?

A)inferential
B)significance
C)precision
D)confidence

Question 40

The smaller the level of confidence,the ________ precise the estimate.

A)more
B)less

Question 41

A matched-pairs design is one example of a situation in which it is appropriate to use the estimation formula for the related samples t.

Question 42

For the same data,increasing the certainty of an estimate will result in a less precise estimate.

Question 43

The least certain,but most precise,estimate is a point estimate.

Question 44

The estimation formula for the one-sample z is
.

Question 45

There is no difference between a point estimate and an interval estimate.

Question 46

The estimation formula for the two-independent sample t is
.

Question 47

As the standard error increases,the precision of an estimate also increases.

Question 48

The population variance must be known to estimate the population mean for the one-sample z.

Question 49

The estimated standard error is used in the formula to estimate the population mean for the one-sample z.

Question 50

The estimated standard error is used in the formula to estimate the population mean for the one-sample t.

Question 51

When the null hypothesis is outside a confidence interval,this indicates that it would likely be retained with hypothesis testing.

Question 52

Two types of estimation are point estimation and interval estimation.

Question 53

To estimate the population mean for the two-independent sample t,the sample size must be known.

Question 54

A point estimate is associated with a high level of confidence that the estimate is in fact equal to the population mean.

Question 55

The smaller the level of confidence,the more precise the estimate.

Question 56

Researchers can infer decisions made in hypothesis testing based on information provided by confidence intervals.

Question 57

The estimation formula for the one-sample t is
.

Question 58

The estimation formula for the related samples t is
.

Question 59

A researcher states that the average child acquires 2.6 taste aversions in his or her lifetime.This is an example of a point estimate.

Question 60

Confidence intervals can be interpreted in terms of the effect size.