Deck 7: Estimation Procedures

Question 1

Because there is always a chance that an EPSEM sample might not be representative,alpha cannot be

A)known.
B)1.00.
C)0.00.
D)less than .10.

Answer 1

0.00.

Question 2

The more efficient the estimate,the more the sampling distribution

A)is evenly spread from the mean to $\pm$ 2 standard deviations.
B)becomes flatter.
C)clusters to the right of the mean.
D)is clustered around the mean.

Answer 2

is clustered around the mean.

Question 3

The sizes of four samples vary as follows:
Sample A,N = 100
Sample B,N = 76
Sample C,N = 1000
Sample D,N = 150
Which sample will produce the most efficient estimate?

A)Sample A
B)Sample B
C)Sample C
D)Sample D

Answer 3

Sample C

Question 4

The goal of estimation procedures is to infer ____ from ____.

A)intervals,estimates
B)bias,efficiency
C)statistics,parameters
D)parameters,statistics

Question 5

The efficiency of any estimator can be improved by

A)increasing the sample size.
B)decreasing the sample size.
C)making the sample representative.
D)changing the sample.

Question 6

From a random sample of 300 state university students,you found that the average number of hours of study time each week is 30 with a standard deviation of 5.A point estimate of the average study time for all state university students would be

A)5.
B)30.
C)300.
D)15 $\pm$ 1 standard deviation.

Question 7

Public opinion polls and election projections are examples of

A)estimation procedures.
B)hypothesis testing.
C)non-statistical research methods.
D)blatant misuse of statistical procedures.

Question 8

We can estimate the probability that sample means and proportions lie within a given distance of the population value because these statistics are

A)unbiased.
B)efficient.
C)random.
D)biaseD.

Question 9

Based on an EPSEM sample of 300 state university students,we estimate that the average number of hours of study time each week is 30 $\pm$ 2.In this example,the population is

A)the 300 state university students.
B)all state university students.
C)unknown.
D)the same as the parameter.

Question 10

The probability that a sample mean is within $\pm$ 1 Z of the population mean is about

A).34.
B).68.
C).95.
D).99.

Question 11

Two sample statistics are unbiased estimators.They are

A)means and proportions.
B)means and standard deviations.
C)medians and modes.
D)proportions and percentages.

Question 12

The larger the sample size (N),the

A)smaller the parameter.
B)greater the efficiency.
C)lower the bias.
D)larger the standard error of the mean.

Question 13

The probability that an interval estimate does not include the population value is called

A)the margin.
B)alpha.
C)an error.
D)the odds.

Question 14

Based on an EPSEM sample of 300 state university students,we estimate that the average number of hours of study time each week is 30 $\pm$ 2.In this example,the parameter is

A)300.
B)30.
C) $\pm$ 2.
D)unknown.

Question 15

In estimation procedures,____ are estimated based on the value of ____.

A)statistics,parameters
B)parameters,statistics
C)values,frequencies
D)sample,populations

Question 16

An estimator is unbiased if the mean of its sampling distribution is equal to

A)the midpoint of the distribution.
B)the sample mean.
C)the population value.
D)the population median.

Question 17

In the United States,between 70% and 80% of the people who do the family grocery shopping are women.This is

A)not a finding which can be generalized.
B)a point estimate.
C)an interval estimate.
D)sexism at its most offensive.

Question 18

The efficiency of a sample estimator is essentially a matter of

A)accuracy.
B)validity.
C)centrality.
D)dispersion.

Question 19

In estimation procedures,the alpha level is

A)the same as the confidence level.
B)the parameter we are trying to estimate.
C)always greater than the standard error.
D)equal to the efficiency ratio minus the bias coefficient.

Question 20

In ____ of the cases,the mean of a sample selected by EPSEM will be more than $\pm$ 3 Z's from the population mean.

A)less than 1%
B)more than 5%
C)more than 90%
D)more than 99%

Question 21

We have used an alpha of 0.01 to estimate the average hours of television viewing for residents in a retirement home.What is the chance that our interval estimate does not contain the true population mean?

A)99%
B)10%
C)1%
D)1/10 of 1%

Question 22

In constructing interval estimates based on sample proportions (P_s),the population proportion (P_u)must be estimated.It is most conservative to estimate P_u at

A)P_s.
B).50.
C).25.
D)1.00.

Question 23

To decrease the probability that a confidence interval will NOT include the population parameter,

A)lower the alpha level.
B)raise the alpha level.
C)increase the bias of the sample statistiC.
D)set efficiency to zero.

Question 24

In the formula for finding a confidence interval when the value of the population standard deviation is unknown,we change N to N - 1.The reason for this change is

A)to correct for the fact that s is biased.
B)the standard deviation of a sample is always greater than the standard deviation of the population.
C)the standard deviation of a sample is unbiased.
D)sample size is much too large.

Question 25

A confidence level of 99% is the same as an alpha level of

A)0.05.
B)0.10.
C)0.01.
D)0.001.

Question 26

An alpha level of 0.05 is the same as a confidence level of

A)99.5%.
B)95%.
C)90.5%.
D)90%.

Question 27

When using sample means as estimators,we usually estimate the population standard deviation with

A)the sample standard deviation.
B)the sampling distribution standard deviation.
C)the population parameter.
D)the Z score.

Question 28

The average weight of a sample of women who attend aerobics classes at the YWCA is 130 pounds.We construct a confidence interval (using an alpha of 0.05)of $\pm$ 3.45.The upper and lower limits of our estimate are

A)130.00 and 133.45.
B)126.55 and 130.45.
C)126.55 and 133.45.
D)unknown;these values will depend on the number of women who are truly serious about exercising.

Question 29

As our confidence in an interval estimate increases,the width of the interval

A)decreases.
B)increases.
C)remains the same.
D)increases or decreases depending on the alpha level.

Question 30

The greater the confidence level,the ____ width of the confidence interval

A)narrower
B)more representative
C)more efficient
D)wider

Question 31

A random sample of 500 reports an average yearly income of $42,000 with a standard deviation of $1000.An estimate of the parameter at the 95% level is about $175 wide.In this research situation,

A)the parameter is $42,000.
B)the sample is unrepresentative.
C)the alpha level is 0.05.
D)the sample mean is $175.

Question 32

A random sample of 200 includes 100 Protestants.The researcher estimates,at the 95% confidence level,that between 43% and 57% of the population is Protestant.In this research situation,

A)alpha is .10.
B)P_u is 95.
C)N is 100.
D)P_s is .50.

Question 33

The most commonly used confidence level is

A)99.5%.
B)95%.
C)90.5%.
D)90%.

Question 34

The sample standard deviation is a biased estimator of the population standard deviation.When using sample means as estimators,we correct for bias in the formula for finding confidence intervals by

A)using N - 1 rather than N.
B)using N rather than N - 1.
C)using s rather than Z.
D)squaring the value of Z.

Question 35

A random sample of 500 reports an average yearly income of $42,000 with a standard deviation of $1000.An estimate of the parameter at the 95% level is about $175 wide.In this research situation,

A)we can be 95% confident that the population mean is 42,000 $\pm$ 175.
B)the sample size is much too small to justify the use of estimation procedures.
C)the alpha level is 1000.
D)the sample mean is $175.

Question 36

In the formulas for constructing interval estimates based on sample proportions,the expression P_u (l - P_u)has a maximum value of

A).50.
B).25.
C)1.00.
D).75.

Question 37

A random sample of 200 includes 100 Protestants.The researcher estimates,at the 95% confidence level,that between 43% and 57% of the population is Protestant.In this research situation,

A)the parameter is 200.
B)P_u is .43 or .57.
C)N is 100.
D)alpha is 0.05.

Question 38

In estimation procedures,as the alpha level decreases,the corresponding Z score

A)moves closer to the mean of the sampling distribution.
B)moves away from the mean of the sampling distribution.
C)becomes negative.
D)becomes positive.

Question 39

In estimation procedures,the Z score that corresponds to an alpha of .05 is

A) $\pm$ 1.96.
B) $\pm$ 2.58.
C) $\pm$ 3.78.
D) $\pm$ 9.78.

Question 40

To increase the probability that a confidence interval will include the population parameter,

A)lower the alpha level.
B)raise the alpha level.
C)increase the bias of the sample statistiC.
D)set efficiency to zero.

Question 41

All other things being equal,larger sample will cost more to process

A)but will not necessarily have narrower confidence intervals.
B)and will always produce narrower confidence intervals.
C)and will always produce wider confidence intervals.
D)but will produce more precise intervals if the confidence level is low.

Question 42

Instruction: For each situation below,construct the 95% confidence interval estimate to the population.Assume that the results are based on a nationally representative sample.Express the estimate in a sentence.
Refer to the instruction.The average number of children for the 945 respondents for which we have information was 1.98 with a standard deviation of 1.04.

Question 43

Wider confidence intervals

A)are sure to include the population value.
B)are less likely to include the population value.
C)are more likely to include the population value.
D)do not alter the chance of including the population value.

Question 44

Sample size and the width of confidence intervals

A)increase at the same rate.
B)increase at different rates: sample size increases faster than interval width.
C)increase at different rates: sample size increases more slowly than interval width.
D)have no relationship to each other.

Question 45

If a researcher changes from the 90% confidence level to the 95% level,the confidence interval will

A)widen.
B)decrease in width.
C)not be affected.
D)widen only if N is greater than 100.

Question 46

The width of an interval estimate can be controlled by

A)changing the confidence level.
B)changing the alpha level.
C)changing the sample size.
D)any of the above

Question 47

Instruction: For each situation below,construct the 95% confidence interval estimate to the population.Assume that the results are based on a nationally representative sample.Express the estimate in a sentence.
Refer to the instruction.The average years of school completed for 734 respondents was 11.9 with a standard deviation of 0.5.

Question 48

To construct the narrowest possible confidence intervals,use ____.

A)small samples
B)large samples
C)the least efficient estimator
D)an unbiased statistic

Question 49

Instruction: For each situation below,construct the 95% confidence interval estimate to the population.Assume that the results are based on a nationally representative sample.Express the estimate in a sentence.
Refer to the instruction.Of the 1220 respondents for whom we have information,178 said that they had been divorced at least once.

Question 50

Which sample size will produce the confidence interval with the smallest width?

A)100
B)200
C)500
D)1000

Question 51

Instruction: For each situation below,construct the 95% confidence interval estimate to the population.Assume that the results are based on a nationally representative sample.Express the estimate in a sentence.
Refer to the instruction.Four hundred and thirty two of the 668 respondents questioned said that they favored capital punishment for people convicted of murder.Ten years ago,in response to the same question,378 out of 703 people were in favor of capital punishment.Has support for capital punishment risen over the ten year period?

Question 52

Polls tracking the popularity of President Bush show

A)dramatic increases in support following both the terrorist attacks of 9-11 and the invasion of Iraq.
B)a dramatic increase in support following 9-11 but no particular change after the invasion of Iraq.
C)a remarkable consistency in popularity that never exceeded 55% and never fell below 50%.
D)low levels of support that have often fallen below 25% approval.

Question 53

Instruction: For each situation below,construct the 95% confidence interval estimate to the population.Assume that the results are based on a nationally representative sample.Express the estimate in a sentence.
Refer to the instruction.Of the 998 respondents questioned,246 identified themselves as Catholic.

Question 54

Instruction: For each situation below,construct the 95% confidence interval estimate to the population.Assume that the results are based on a nationally representative sample.Express the estimate in a sentence.
Refer to the instruction.The average age of the 1225 respondents was 25.3 with a standard deviation of 1.9.

Question 55

Polls tracking the presidential election of 2004 showed that

A)Bush lead by a clear margin from start to finish.
B)Kerry lead by a clear margin until just a week before election day.
C)the race was "too close to call" during much of the campaign.
D)voter turnout would be extraordinarily high.

Question 56

As sample size increases,confidence interval width

A)increases.
B)decreases.
C)remains the same.
D)changes proportionally.

Question 57

In a two person race,if the Republican presidential candidate is projected to attract 44% $\pm$ 3% of the vote,and the Democratic candidate is projected to attract 46% $\pm$ 3% of the vote,then

A)the Republican is the probable winner.
B)the Democrat is the probable winner.
C)neither candidate will win a majority of votes in the electoral college.
D)the race is "too close to call."