Question 1

When using Student's t to compute an interval estimate,________.

Accepted Answer

A) we assume that the samples are collected from populations that are uniformly distributed 
B) we estimate the population mean based on the sample mean 
C) we use the z-distribution 
D) we assume that the samples are collected from normally distributed populations 
A) we assume that the samples are collected from populations that are uniformly distributed 
B) we estimate the population mean based on the sample mean 
C) we use the z-distribution 
D) we assume that the samples are collected from normally distributed populations

Question 2

When a confidence interval for a population mean is constructed from sample data,________.

Accepted Answer

A) we can conclude that the population mean is in the interval 
B) we can conclude that the population mean is not in the interval 
C) we can conclude,for an infinite number of samples and corresponding confidence intervals,that the population mean is in a stated percentage of the intervals 
D) we cannot make any inferences 
A) we can conclude that the population mean is in the interval 
B) we can conclude that the population mean is not in the interval 
C) we can conclude,for an infinite number of samples and corresponding confidence intervals,that the population mean is in a stated percentage of the intervals 
D) we cannot make any inferences

Question 3

A local company wants to evaluate their quality of service by surveying their customers. Their budget limits the number of surveys to 100. What is their maximum error of the estimated mean quality for a 95% level of confidence and an estimated standard deviation of 5?

Accepted Answer

A) 0.9604 
B) 0.98 
C) 1.96 
D) 5% 
A) 0.9604 
B) 0.98 
C) 1.96 
D) 5%

Question 4

Which of the following is not necessary to determine how large a sample to select from a population?

Accepted Answer

A) The level of confidence in estimating the population parameter 
B) The size of the population 
C) The maximum allowable error in estimating the population parameter 
D) An estimate of the population variation 
A) The level of confidence in estimating the population parameter 
B) The size of the population 
C) The maximum allowable error in estimating the population parameter 
D) An estimate of the population variation

Question 5

A sample of 25 is selected from a known population of 100 elements. What is the finite population correction factor?

Accepted Answer

A) 8.66 
B) 75 
C) 0.87 
D) Cannot be determined 
A) 8.66 
B) 75 
C) 0.87 
D) Cannot be determined

Question 6

A confidence interval for a population mean ________.

Accepted Answer

A) estimates the population range 
B) estimates a likely interval for a population mean 
C) estimates likelihood or probability 
D) estimates the population standard deviation 
A) estimates the population range 
B) estimates a likely interval for a population mean 
C) estimates likelihood or probability 
D) estimates the population standard deviation

Question 7

A confidence interval for a population proportion uses the uniform distribution to approximate the binomial distribution.

Accepted Answer

A) True 
 B)False

Question 8

A bank wishes to estimate the mean credit card balance owed by its customers. The population standard deviation is estimated to be $300. If a 98% confidence interval is used and an interval of $75 is desired,how many customers should be sampled?

Accepted Answer

A) 44 
B) 212 
C) 629 
D) 87 
A) 44 
B) 212 
C) 629 
D) 87

Question 9

The 95% confidence interval states that 95% of the sample means of a specified sample size selected from a population will lie within plus and minus 1.96 standard deviations of the hypothesized population mean.

Accepted Answer

A) True 
 B)False

Question 10

A survey of households in a small town showed that in 850 of 1,200 sampled households,at least one member attended a town meeting during the year. Using the 99% level of confidence,what is the confidence interval for the proportion of households represented at a town meeting?

Accepted Answer

A) [0.674,0.742] 
B) [0.655,0.705] 
C) [0.665,0.694] 
D) [0.679,0.680] 
A) [0.674,0.742] 
B) [0.655,0.705] 
C) [0.665,0.694] 
D) [0.679,0.680]

Question 11

A survey of an urban university (population of 25,450)showed that 750 of 1,100 students sampled attended a home football game during the season. Using the 90% level of confidence,what is the confidence interval for the proportion of students attending a football game?

Accepted Answer

A) [0.7510,0.8290] 
B) [0.6592,0.7044] 
C) [0.6659,0.6941] 
D) [0.6795,0.6805] 
A) [0.7510,0.8290] 
B) [0.6592,0.7044] 
C) [0.6659,0.6941] 
D) [0.6795,0.6805]

Question 12

A random sample of 20 items is selected from a population. When computing a confidence interval for the population mean,what number of degrees of freedom should be used to determine the appropriate t-value?

Accepted Answer

A) 20 
B) 19 
C) 21 
D) 25 
A) 20 
B) 19 
C) 21 
D) 25

Question 13

Knowing the population standard deviation,a 95% confidence interval infers that the population mean ________.

Accepted Answer

A) is between 0 and 100% 
B) is within ±1.96 standard deviations of the sample mean 
C) is within ±1.96 standard errors of the sample mean 
D) is too large 
A) is between 0 and 100% 
B) is within ±1.96 standard deviations of the sample mean 
C) is within ±1.96 standard errors of the sample mean 
D) is too large

Question 14

The finite population correction (FPC)factor is used to adjust the z-statistic or t-statistic.

Accepted Answer

A) True 
 B)False

Question 15

A z-statistic is used for a problem involving any sample size and an unknown population standard deviation.

Accepted Answer

A) True 
 B)False

Question 16

How is the t-distribution similar to the standard z-distribution?

Accepted Answer

A) Both are discrete distributions. 
B) Both are skewed distributions. 
C) Both are families of distributions. 
D) Both are continuous distributions. 
A) Both are discrete distributions. 
B) Both are skewed distributions. 
C) Both are families of distributions. 
D) Both are continuous distributions.

Question 17

A survey of 50 retail stores revealed that the average price of a microwave was $375 with a sample standard deviation of $20. Assuming the population is normally distributed,what is the 99% confidence interval to estimate the true cost of the microwave?

Accepted Answer

A) $367.42 to $382.58 
B) $315.00 to $415.00 
C) $323.40 to $426.60 
D) $335.82 to $414.28 
A) $367.42 to $382.58 
B) $315.00 to $415.00 
C) $323.40 to $426.60 
D) $335.82 to $414.28

Question 18

The finite population correction factor is applied when the population size is known.

Accepted Answer

A) True 
 B)False

Question 19

A research firm needs to estimate within 3% the proportion of junior executives leaving large manufacturing companies within three years. A 0.95 degree of confidence is to be used. Several years ago,a study revealed that 21% of junior executives left their company within three years. To update this study,how many junior executives should be surveyed?

Accepted Answer

A) 594 
B) 612 
C) 709 
D) 897 
A) 594 
B) 612 
C) 709 
D) 897

Question 20

A student wanted to construct a 95% confidence interval for the mean age of students in her statistics class. She randomly selected nine students. Their mean age was 19.1 years,with a sample standard deviation of 1.5 years. What is the 95% confidence interval for the population mean?

Accepted Answer

A) [0.97,3.27] 
B) [15.64,22.56] 
C) [17.97,20.23] 
D) [17.95,20.25] 
A) [0.97,3.27] 
B) [15.64,22.56] 
C) [17.97,20.23] 
D) [17.95,20.25]

When using Student's t to compute an interval estimate,________.

When a confidence interval for a population mean is constructed from sample data,________.

A local company wants to evaluate their quality of service by surveying their customers. Their budget limits the number of surveys to 100. What is their maximum error of the estimated mean quality for a 95% level of confidence and an estimated standard deviation of 5?

Which of the following is not necessary to determine how large a sample to select from a population?

A sample of 25 is selected from a known population of 100 elements. What is the finite population correction factor?

A confidence interval for a population mean ________.

A confidence interval for a population proportion uses the uniform distribution to approximate the binomial distribution.

A bank wishes to estimate the mean credit card balance owed by its customers. The population standard deviation is estimated to be $300. If a 98% confidence interval is used and an interval of $75 is desired,how many customers should be sampled?

The 95% confidence interval states that 95% of the sample means of a specified sample size selected from a population will lie within plus and minus 1.96 standard deviations of the hypothesized population mean.

A survey of households in a small town showed that in 850 of 1,200 sampled households,at least one member attended a town meeting during the year. Using the 99% level of confidence,what is the confidence interval for the proportion of households represented at a town meeting?

A survey of an urban university (population of 25,450)showed that 750 of 1,100 students sampled attended a home football game during the season. Using the 90% level of confidence,what is the confidence interval for the proportion of students attending a football game?

A random sample of 20 items is selected from a population. When computing a confidence interval for the population mean,what number of degrees of freedom should be used to determine the appropriate t-value?

Knowing the population standard deviation,a 95% confidence interval infers that the population mean ________.

The finite population correction (FPC)factor is used to adjust the z-statistic or t-statistic.

A z-statistic is used for a problem involving any sample size and an unknown population standard deviation.

How is the t-distribution similar to the standard z-distribution?

A survey of 50 retail stores revealed that the average price of a microwave was $375 with a sample standard deviation of $20. Assuming the population is normally distributed,what is the 99% confidence interval to estimate the true cost of the microwave?

The finite population correction factor is applied when the population size is known.

A student wanted to construct a 95% confidence interval for the mean age of students in her statistics class. She randomly selected nine students. Their mean age was 19.1 years,with a sample standard deviation of 1.5 years. What is the 95% confidence interval for the population mean?

What Is Statistics

Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation

Describing Data: Numerical Measures

Describing Data: Displaying and Exploring Data

A Survey of Probability Concepts

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Methods and the Central Limit Theorem

One-Sample Tests of Hypothesis

Two-Sample Tests of Hypothesis

Analysis of Variance

Correlation and Linear Regression

Multiple Regression Analysis

Nonparametric Methods: Nominal Level Hypothesis Tests

Nonparametric Methods: Analysis of Ordinal Data

Index Numbers

Time Series and Forecasting

Statistical Process Control and Quality Management

An Introduction to Decision Theory

Filters

Exam 9: Estimation and Confidence Intervals

When using Student's t to compute an interval estimate,________.

When a confidence interval for a population mean is constructed from sample data,________.

A local company wants to evaluate their quality of service by surveying their customers. Their budget limits the number of surveys to 100. What is their maximum error of the estimated mean quality for a 95% level of confidence and an estimated standard deviation of 5?

Which of the following is not necessary to determine how large a sample to select from a population?

A sample of 25 is selected from a known population of 100 elements. What is the finite population correction factor?

A confidence interval for a population mean ________.

A confidence interval for a population proportion uses the uniform distribution to approximate the binomial distribution.

A bank wishes to estimate the mean credit card balance owed by its customers. The population standard deviation is estimated to be $300. If a 98% confidence interval is used and an interval of $75 is desired,how many customers should be sampled?

The 95% confidence interval states that 95% of the sample means of a specified sample size selected from a population will lie within plus and minus 1.96 standard deviations of the hypothesized population mean.

A survey of households in a small town showed that in 850 of 1,200 sampled households,at least one member attended a town meeting during the year. Using the 99% level of confidence,what is the confidence interval for the proportion of households represented at a town meeting?

A survey of an urban university (population of 25,450)showed that 750 of 1,100 students sampled attended a home football game during the season. Using the 90% level of confidence,what is the confidence interval for the proportion of students attending a football game?

A random sample of 20 items is selected from a population. When computing a confidence interval for the population mean,what number of degrees of freedom should be used to determine the appropriate t-value?

Knowing the population standard deviation,a 95% confidence interval infers that the population mean ________.

The finite population correction (FPC)factor is used to adjust the z-statistic or t-statistic.

A z-statistic is used for a problem involving any sample size and an unknown population standard deviation.

How is the t-distribution similar to the standard z-distribution?

A survey of 50 retail stores revealed that the average price of a microwave was $375 with a sample standard deviation of $20. Assuming the population is normally distributed,what is the 99% confidence interval to estimate the true cost of the microwave?

The finite population correction factor is applied when the population size is known.

A student wanted to construct a 95% confidence interval for the mean age of students in her statistics class. She randomly selected nine students. Their mean age was 19.1 years,with a sample standard deviation of 1.5 years. What is the 95% confidence interval for the population mean?

What Is Statistics

Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation

Describing Data: Numerical Measures

Describing Data: Displaying and Exploring Data

A Survey of Probability Concepts

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Methods and the Central Limit Theorem

One-Sample Tests of Hypothesis

Two-Sample Tests of Hypothesis

Analysis of Variance

Correlation and Linear Regression

Multiple Regression Analysis

Nonparametric Methods: Nominal Level Hypothesis Tests

Nonparametric Methods: Analysis of Ordinal Data

Index Numbers

Time Series and Forecasting

Statistical Process Control and Quality Management

An Introduction to Decision Theory

Filters