Deck 7: Estimation

Question 1

SELECT ALL THAT APPLY.If a 95% confidence level is selected,then

A)the corresponding Z score is 2.58.
B)the probability of a selected sample falling in this interval is 0.95.
C)there is a 5% chance of the interval being incorrect.
D)5 chances out of 100 will fall in the interval.

Answer 1

the probability of a selected sample falling in this interval is 0.95.
there is a 5% chance of the interval being incorrect.

Question 2

Where is the most common application of estimation using confidence intervals usually found?

A)Statistics textbooks
B)Scholarly journals
C)Opinion polls
D)GSS data

Answer 2

Opinion polls

Question 3

A point estimate is an estimate where a

A)sample statistic is used to estimate the exact value of a population parameter.
B)sample statistic is used to estimate a range of possible values of a population parameter.
C)population parameter is used to estimate the exact value of a sample statistic population.
D)parameter is used to estimate a range of possible values of a sample statistic.

Answer 3

sample statistic is used to estimate the exact value of a population parameter.

Question 4

Because population parameters are typically unknown,we use the ______ to estimate the value of the standard error.

A)sample standard deviation
B)population standard deviation
C)sample proportion
D)population proportion

Question 5

For which of the following statistic the confidence intervals are usually constructed?

A)N
B)Mode
C)Mean
D)Variance

Question 6

The radius of a confidence interval is called the

A)standard deviation.
B)confidence level.
C)population parameter.
D)margin of error.

Question 7

What is the goal of most research?

A)To support the null hypothesis
B)To find the population parameter
C)To seek a sample
D)To determine the confidence interval

Question 8

Ranges of values within which the population parameter may fall are called

A)interval estimates.
B)margin intervals.
C)point estimates.
D)standard levels.

Question 9

Widening the confidence interval from 95% to 99% increases the ______ but decreases the ______.

A)precision;reliability
B)precision;confidence
C)confidence;precision
D)accuracy;precision

Question 10

If the value of the sample standard deviation increases,what happens to the confidence interval?

A)It becomes wider.
B)It becomes more precise.
C)It does not change.
D)It narrows.

Question 11

Assuming that a sample (N = 504)has a sample standard deviation of 2.26,what is the estimated standard error?

A).004
B).101
C)223.009
D).226

Question 12

Which two quantities are needed to estimate the standard error of the proportions toward the further estimation of confidence intervals for proportions?

A)Sample mean and sample standard deviation
B)Population mean and population standard deviation
C)Sample proportion and sample size
D)Population proportion and population size

Question 13

Sample size and the confidence level width have a(n)______ relationship.

A)symbiotic
B)inverse
C)synonymous
D)identical

Question 14

Which of the following is true about the relationship between the population mean and the mean of the sampling distribution?

A)population mean = mean of the sampling distribution
B)population mean ≠ mean of the sampling distribution
C)population mean < mean of the sampling distribution
D)population mean > mean of the sampling distribution

Question 15

Using the normal distribution,we know that ______ % of all random sample means will fall within ±1.96 standard errors of the true population mean.

A)68
B)95
C)99
D)100

Question 16

The actual percentage of Americans who support gay and lesbian relations is an example of a(n)

A)estimation.
B)sample.
C)confidence interval.
D)population parameter.

Question 17

Which of the following examples illustrates estimation?

A)The actual percentage of unemployed Americans
B)The varying valid percentages of Republicans and Democrats who closely follow controversial political news
C)The actual average level of education in the United States
D)The percentage of Americans who favor gay and lesbian relations as approximated by the Gallup organization

Question 18

The likelihood that a specified interval will contain the population parameter is referred to as

A)an upper bound.
B)a lower bound.
C)the confidence level.
D)the margin of error.

Question 19

The formula is used to estimate the

A)mean.
B)standard error.
C)Z score.
D)confidence interval for mean.

Question 20

Assuming that a sample (N = 504)has a sample standard deviation of 2.26,what is the upper bound of a 95% confidence interval if the sample mean is 2.96?

A)2.76
B)2.96
C)3.16
D)5.94

Question 21

To establish a confidence interval for a proportion,add or subtract from the mean the product of the standard error and the Z value corresponding to the confidence level.

Question 22

SELECT ALL THAT APPLY.Information on the population can be drawn from

A)sample mean.
B)sample size.
C)sample standard deviation.
D)number of subgroups in the population.

Question 23

Typically,both the mean and the standard deviation of the population are unknown.

Question 24

If the sample size goes up,the confidence level becomes less precise.

Question 25

A sample of 150 U.S.adults is composed of 100 women and 50 men.Estimate the confidence interval for the female population with 99% confidence.

Question 26

Provide a substantive interpretation of the following 99% confidence interval: (.25,.41).

Question 27

What is the effect on a confidence interval if one decreases both sample size and the level of confidence?

Question 28

When p > 0.50,a larger sample is required to meet the assumptions of normality.

Question 29

If the level of confidence goes down (from 99% to 95%),the confidence level becomes less precise.

Question 30

A sample of 150 U.S.adults is composed of 100 women and 50 men.Estimate the standard error of the proportions for the female population.

Question 31

In a survey sample of 83 respondents,the mean number of hours worked per week is 39.04,with a standard deviation of 11.51.The sample size is 83.Estimate the value of the standard error.

Question 32

If the value of the sample standard deviation goes up,the confidence level becomes more precise.

Question 33

In a survey sample of 83 respondents,the mean number of hours worked per week is 39.04,with a standard deviation of 11.51.Calculate a 95% confidence interval for these data.

Question 34

SELECT ALL THAT APPLY.Confidence level

A)is the range of values within which the population parameter is estimated to fall.
B)is the likelihood that a specified interval will contain the population parameter.
C)can be expressed as a percentage.
D)can be expressed as a probability.

Question 35

A sample of 150 U.S.adults is composed of 100 women and 50 men.Estimate the confidence interval for the male population with 99% confidence.

Question 36

A sample of 150 U.S.adults is composed of 100 women and 50 men.Estimate the standard error of the proportions for the male population.

Question 37

The standard error of the proportion .35 with sample N = 1700 is .001.

Question 38

SELECT ALL THAT APPLY.If the sample standard deviation of a sample N = 1001 is 2.60 and sample mean is 2.94,then

A)estimate standard error is .8.
B)the upper bound with 95% confidence level is 3.10.
C)the lower bound with 95% confidence level is 2.78.
D)the Z value corresponding to a 95% confidence level is 2.58.

Question 39

SELECT ALL THAT APPLY.Margin of error

A)refers to confidence intervals.
B)is equal to standard error of the mean.
C)is equal to standard error of the proportion.
D)is the radius of confidence intervals.

Question 40

A process whereby we select a random sample from a population and use a sample statistic to estimate a population parameter is known as a point estimate.

Question 41

In a survey sample of 1000 respondents,the mean annual salary is $32,245,with a standard deviation of 4021.54.Estimate the value of the standard error.

Question 42

Provide a hypothetical numerical example which demonstrates that the precision of a confidence interval is in part a function of sample size.

Question 43

In a survey sample of 83 respondents,about 30.1% of the sample work less than 40 hours per week.Calculate a 68% confidence interval for the proportion of persons who work 40 hours or more per week.

Question 44

In a survey sample of 1000 respondents,the mean annual salary is $32,245,with a standard deviation of 4021.54.Calculate a 99% confidence interval for these data.

Question 45

Briefly describe how you would establish a confidence interval for a mean or proportion.

Question 46

Suppose that a researcher calculated a 95% confidence interval of (36.56,41.52).Provide a one or two sentence interpretation of this result.

Question 47

In a survey sample of 83 respondents,about 30.1 percent of the sample work less than 40 hours per week.What is the estimated standard error for the group of respondents who work 40 hours or more per week?

Question 48

In a survey sample of 1000 respondents,the mean annual salary is $32,245,with a standard deviation of 4021.54.Calculate a 95% confidence interval for these data.

Question 49

In a survey sample of 83 respondents,about 30.1 percent of the sample work less than 40 hours per week.What is the estimated standard error of the proportion for this group?

Question 50

In a survey sample of 83 respondents,about 30.1 percent of the sample work less than 40 hours per week.Calculate a 68% confidence interval for the proportion of persons who work less than 40 hours per week.