Deck 6: Introduction to Inferential Statistics Sampling the Sampling Distribution

Question 1

A major problem with non-probability samples is that they

A) do not allow us to generalize to a population
B) are far too expensive
C) are much too large
D) are always very small

Answer 1

do not allow us to generalize to a population

Question 2

For a simple random sample, each case and each combination of cases in the population must

A) be representative
B) be included in the sample
C) be contacted by the researcher
D) have an equal probability of being chosen for the sample

Answer 2

have an equal probability of being chosen for the sample

Question 3

If a sample is representative, it

A) is very large
B) is restricted to the calculation of parameters only
C) reproduces the characteristics of the population
D) resembles the sampling distribution

Answer 3

reproduces the characteristics of the population

Question 4

Compared to probability samples, non-probability samples

A) are usually cheaper to assemble
B) are always much larger
C) are usually more expensive to assemble
D) allow for generalizations to populations

Question 5

Unless a sample is __________, it cannot be used to make accurate generalizations to a population.

A) very large
B) non-probability
C) representative
D) stratified

Question 6

Samples are to populations as

A) big is to little
B) central tendency is to dispersion
C) measures are to variables
D) statistics are to parameters

Question 7

The purpose of inferential statistics is to acquire knowledge of the ____________ from the ___________ by means of the _____________ distribution

A) population … sample … sampling
B) sample … sampling … population
C) inductive … empirical … stratified
D) theoretical … empirical …theoretical

Question 8

The mean age of all graduates of a certain college is 35. If the population distribution is normal, the mean of any sampling distribution of sample mean ages of graduates of this college will be

A) within plus or minus 1 standard deviation of 35
B) close to 35
C) 35
D) determined by the size of the distribution

Question 9

A researcher tests a theory about sexism by administering a survey to the 200 students in her sociology classes. This sample is best characterized as a

A) simple sample
B) random sample
C) non-probability sample
D) sampling distribution

Question 10

The sampling distribution links the ________ to the __________ .

A) stratified … EPSEM
B) statistical … empirical
C) sample … population
D) empirical … real

Question 11

What are the three distributions involved in every application of inferential statistics?

A) sample, sampling, and population
B) sample, EPSEM, representative
C) EPSEM, random, probability
D) sampling, percentage, normal

Question 12

The goal of all techniques for selecting probability samples is to select samples that are

A) very large
B) non-random
C) easily located
D) representative

Question 13

Social scientists gather data from samples instead of populations because

A) samples are much larger and more complete
B) samples are more trustworthy
C) populations are often too large to test
D) samples are more meaningful and interesting

Question 14

In a sampling distribution of sample means, most of the sample means will

A) cluster around the true population value
B) be below the population mean in value
C) be above the population mean in value
D) not follow any particular pattern

Question 15

To select a simple random sample, a researcher needs

A) a list of the population and system for selecting cases according to EPSEM
B) a list of the sample and a well-developed sampling distribution
C) a sampling distribution and a table of random numbers
D) a parameter, the median, and the variance

Question 16

Statistics are to parameters as

A) samples are to populations
B) populations are to samples
C) medians are to standard deviations
D) percentages are to proportions

Question 17

Statistics are characteristics of samples while ________ are characteristics of ___________.

A) percentages … populations
B) medians … clusters
C) parameters … samples
D) parameters … populations

Question 18

The fundamental principle of probability sampling is that a sample selected by________ is very likely to be __________.

A) EPSEM, representative
B) polling, large
C) telephone polls, cheap
D) nonprobability methods, representative

Question 19

Unlike the sample and population distributions, the sampling distribution is

A) empirical
B) theoretical
C) random
D) EPSEM

Question 20

A researcher questioned 45 randomly-selected members of the freshman class about their experiences drinking alcohol and used these responses to estimate the drinking behavior of the entire freshman class of 1500. In this example, the 45 interviewees were the __________ and the ___________ was the population

A) sample … student body
B) parameters … freshman class
C) statistics … parameters
D) sample … freshman class

Question 21

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 22

The Central Limit Theorem states that as sample size becomes large

A) the sampling distribution of sample means approaches normality
B) the sampling distribution of sample means becomes larger
C) the population distribution becomes normal
D) the sample distribution becomes normal

Question 23

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

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

Question 24

From a random sample of 300 students at a state university, you find the average number of hours of study time each week is 30 with a standard deviation of 5. In this research situation,

A) the sample is too small
B) the population consists of the 300 students surveyed
C) the sample is the 300 students surveyed
D) the parameter is 30

Question 25

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 26

According to the theorems presented in Chapter 6, we can be sure that the sampling distribution is normal if

A) the population is small
B) the population is normal
C) the sample is stratified
D) the sample is normal

Question 27

I surveyed 48 randomly-selected residents of the apartment complex where I live to determine their voting habits. I can only use this information to generalize to all the residents if

A) there is evidence of a normal population distribution
B) the 48 residents all have the same voting habits
C) the 48 residents are equally divided in their voting habits
D) the sample distribution is not normal in shape

Question 28

The theorems presented in Chapter 6 tell us that if a sample is "large" the sampling distribution will be

A) the same shape as the population
B) normal
C) small
D) irrelevant

Question 29

When we use larger samples (N > 100) we can assume a normal sampling distribution because of

A) common sense
B) the Central Limit Theorem
C) what we know about the population
D) what we know about the sample

Question 30

In comparing a sampling distribution with a population distribution,

A) there will always be more variance in the sampling distribution
B) there will always be more variance in the population distribution
C) the two distributions will become identical as the sample size increases
D) the two distributions will always be the same

Question 31

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 32

The efficiency of a sample estimator is essentially a matter of

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

Question 33

The standard error of the mean is the same thing as

A) the standard deviation of a sample
B) the standard deviation of a population
C) the standard deviation of a sampling distribution
D) the variance of a sample

Question 34

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 35

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 36

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 37

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 38

Using the General Social Survey as an example, the concept of the sampling distribution allows us to link the sample to the population of

A) the sample
B) the variance
C) the respondents
D) all adult Americans

Question 39

According to the text, the General Social Survey demonstrates that, since the 1970s, American attitudes about homosexuality have

A) grown more tolerant
B) grown more intolerant
C) not changed
D) grown more tolerant everywhere except in the Southwest

Question 40

The goal of estimation is to infer ___________ from ____________.

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

Question 41

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 42

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 43

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

Question 44

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 45

To construct the narrowest possible confidence intervals, use

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

Question 46

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 47

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

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

Question 48

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 49

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 50

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) Pu is 95
C) N is 100
D) Ps is .50

Question 51

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 52

According to a study reported in the text, Americans report that the happiest day of 2013 was

A) Christmas
B) Saturday
C) Memorial Day
D) Thanksgiving

Question 53

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 54

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 55

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 56

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 57

Most polls conducted just before the 2012 presidential election showed that

A) Obama would probably win
B) Romney would probably win
C) the race was "too close to call"
D) voter turnout would be extraordinarily high