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- 1. Multiple Choice
confidence level
tells how close the estimate tends to be to the unknows parameter in repeated random sampling
the success rate of the method that produces the confidence interval.
the specific value of a point estimator
a statistic that provides an estimate of a population parameter
- 2. Multiple Choice
point estimator
a statistic that provides an estimate of a population parameter
the specific value of a point estimator
describes how far mean x will be from u.
tells how close the estimate tends to be to the unknown parameter in repeated random sampling.
- 3. Multiple Choice
confidence interval
obtained from the sampling distribution
gives overall success rate of the method for calculating the confidence interval.
gives an interval of plausible values for a parameter.
a multiplier that makes the interval wide enough to have the stated capture rate
- 4. Multiple Choice
critical value
a multiplier that makes the interval wide enough to have the stated capture rate.
gives an interval of plausible values for a parameter
gives the overall success rate of the method for calculating the confidence interval
statistic that provides an estimate of a population parameter
- 5. Multiple Choice
standard error
when the standard deviation of a statistic is estimated from data
based on the sample mean of an SRS
uses sample data to estimate an unknown population parameter
success rate of the method that produces the interval.
- 6. Multiple Choice
One reason for using t distribution instead of the standard normal curve to find critical values when calculating a level C confidence interval for a population mean is that
z can be used only for large samples
z requires that you know the population standard deviation
z requires that you can regard your data as an SRS from the population
z requires that the sample size is at most 10% of the population size.
- 7. Multiple Choice
A quality control inspector will measure the salt content in a random sample of bags of potato chips from an hors of production. Which of the following would result in the smallest margin of error in estimating the mean salt content.
90 percent confidence; n-25
90 percent confidence; n=50
95 percent confidence; n=25
95 percent confidence; n=50
- 8. Multiple Choice
The Gallup poll interviews 1600 people. of these, eighteen percent say that they jog regularly. the new report adds: " The poll had a margin of error of plus or minus three percentage points at a 95 percent confidence level." You can safely conclude that
95 percent of all Gallup Poll samples like this one give answers within three percent of the true population valve.
the percent of the population who jog is certain to be between 15 percent and 21 percent.
95 percent of the population jog between 15 and 21 percent of the time
we can be 95 percent confident that the sample proportion is captured by the confidence interval.
- 9. Multiple Choice
The weights in pounds of three adult males are 160,215, and 195. The standard error of the mean of these three weights is.
190
27.84
22.73
16.07
- 10. Multiple Choice
In preparing to construct a one-sample t interval for a population mean, suppose we are not sure if the population distribution is Normal. IN which of the following circumstances would we not be safe constructing the interval based on an SRS of size 24 from the population
A stemplot of the data is roughly bell shaped
a histogram of the data shows slight skewness
a boxplot of the data has a large outlier
the sample standard deviation is large.
- 11. Multiple Choice
Many television viewers express doubts about the validity of certain commercials. in a n attempt to answer their critics, Timex group USA wishes to estimate the proportion of consumers who believe what is shown in Timex television commercials. What is the smallest number of consumers that Timex can survey to guarantee a margin of error of 0.05 or less at a 99% confidence interval.
550
600
700
750
- 12. Multiple Choice
You want to compute a 90% confidence interval for the man of a population with unknown population standard deviation. The sample size is 30. The value of t* you would use for this interval is
1.645
1.699
1.697
1.96
- 13. Multiple Choice
A 90% confidence interval for the mean of a population is computed from a random sample and is found to be 9 plus or minus 3. Which of the following could be the 95% confidence interval based on the same data.
9 plus or minus 2
9 plus or minus 3
9 plus or minus 4
9 plus or minus 8
- 14. Multiple Choice
suppose we want a 90 percent confidence interval for the average amount spent on books by freshman in their first year at a major university. the interval is to have a margin of error of $2. Based on last year's book sales we estimate that the standard deviation of the amount spent will be close to $30. The number of observations required is closet to:
25
30
608
609
- 15. Multiple Choice
A telephone poll of an SRS of 1234 adults found that 62% are generally satisfied with their lives. The announced margin or error for the poll was 3%. Does the margin of error account for the fact that some adults do not have telephones.
yes. the margin of error includes all sources of error in the poll
yes. taking an SRS eliminates any possible bias in estimating the population proportion.
no. the margin of error includes nonresponse but not under coverage
no. the margin of error only includes sampling variability.
- 16. Multiple Choice
A census bureau report on the income of americans says that with 90% confidence the median income of all us households in a recent year was $57,005 with a margin of error of plus or minus 742. this means that.
90% of all households had incomes in the range 57,005 plus or minus 742.
we can be sure that the median income for all households in the country lies in the interval 57,005 plus or minus 742.
90% of the households in the sample interviewed by the census bureau had incomes in the interval 57,005 plus or minus 742.
the census bureau got the result 57,005 plus or minus 742 using a method that will capture the true median income %90 of the time when used repeatedly.
- 17. Multiple Choice
A gallup poll found that only 28% of American adults expect to inherit money or valuable possessions from a relative. The poll's margin or error was three percentage points at a 95% confidence interval
the poll used a method that gets an answer within three percent of the truth about the population 95% of the time.
the percent of all adults who expect an inheritance is between 25 and 31 percent.
if gallup takes another poll on this issue, the results of the second poll will lie between 25 and 31 percent
theres a 95% chance that the percent of all adults who expect an inheritance is between 25 and 31 percent.
- 18. Multiple Choice
You want to design a study to estimate the proportion of students at your school who agree with the statement, " The student government is an effective organization for expressing the needs of students to the administration." You will use a 95% interval, and you would like the margin of error to be .05 or less. The minimum sample size required is
22
271
385
769
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