Deck 7: Estimation Procedures

Question 1

The sizes of four samples vary as follows: Sample A, N = 100 Sample B, N = 76Sample 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 1

C

Question 2

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

Answer 2

C

Question 3

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%

Answer 3

C

Question 4

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 5

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 6

The goal of estimation procedures is to infer ___________ from ____________.

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

Question 7

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 8

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 ± 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 9

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 10

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 11

The efficiency of a sample estimator is essentially a matter of________.

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

Question 12

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 uat________.

A) P s
B) )50
C) )25
D) 1.00

Question 13

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

A) ± 1.96
B) ± 2.58
C) ± 3.78
D) ± 9.78

Question 14

The more efficient the estimate, the more the sampling distribution________.

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

Question 15

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 16

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 17

In the formulas for constructing interval estimates based on sample proportions, the expression P u(l - P u) has a maximum value of________.

A) 0.50
B) 0.25
C) 1.00
D) 0.75

Question 18

To calculate the confidence interval based on sample means, you need all but which of the following________.

A) sample mean.
B) Z score determined by alpha level.
C) standard error of the mean.
D) standard deviation of the population.

Question 19

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 20

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 21

The probability that a sample mean is within±1 Z of the population mean is about________.

A) 0.34.
B) 0.68.
C) 0.95.
D) 0.99.

Question 22

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 ± 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 23

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 ± 2. In this example, the parameter is________.

A) 300.
B) 30.
C) ± 2.
D) unknown.

Question 24

In ________ of the cases, the mean of a sample selected by EPSEM will be more than±3 Z's from the population mean.

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

Question 25

Calculate the confidence interval:________. Of the 1220 respondents for whom we have information, 178 said that they had been divorced at least once.

Question 26

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 answer choices

Question 27

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 28

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

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

Question 29

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 30

In a two person race, if the Republican presidential candidate is projected to attract 44%±3% of the vote and the Democratic candidate is projected to attract 46%±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."

Question 31

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 32

To construct the narrowest possible confidence intervals, use __________.________.

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

Question 33

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 34

In the United States, based on the responses of a random sample to a survey, 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 biased estimate.
C) a confidence interval estimate.
D) sexism at its most offensive.

Question 35

If you have a sample statistic and an unknown population standard deviation, you would use which formula to calculate the confidence interval.________.

A)
B)
C)
D) None of these choices are correct.

Question 36

A reputable poll will include in its description, at the very minimum, the________.

A) standard deviation.
B) margin of error.
C) standard error of the population.
D) confidence intervals.

Question 37

Sample proportions are________.

A) biased.
B) theoretical.
C) unbiased.
D) None of these choices are correct.