Question 1

When using the t distribution to calculate a confidence interval, we assume that the population of interest is normal or nearly normal.

Accepted Answer

A) True 
 B)False

Question 2

A sample of 500 students is selected from a known population of 15000 students to construct a 99% confidence interval for the average SAT score. What correction factor should be used to compute the standard error?

Accepted Answer

A)  0.9499 
B)  0.9832 
C)  2.5760 
D)  Cannot be determined 
A)  0.9499 
B)  0.9832 
C)  2.5760 
D)  Cannot be determined

Question 3

Which of the following is a point estimate for the population mean (µ)?

Accepted Answer

A)  σ 
B)  x/n 
C)    
D)  s 
A)  σ 
B)  x/n 
C)    
D)  s

Question 4

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 5

A university surveyed recent graduates of the English Department for their starting salaries. Four hundred graduates returned the survey. The average salary was $25,000. The population standard deviation was $2,500. What is the 95% confidence interval for the mean salary of all graduates from the English Department?

Accepted Answer

A)  [$22,500, $27,500] 
B)  [$24,755, $25,245] 
C)  [$24,988, $25,012] 
D)  [$24,600, $25,600] 
A)  [$22,500, $27,500] 
B)  [$24,755, $25,245] 
C)  [$24,988, $25,012] 
D)  [$24,600, $25,600]

Question 6

The population variation has little or no effect in determining the size of a sample selected from the population.

Accepted Answer

A) True 
 B)False

Question 7

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 8

An interval estimate is a single value used to estimate a population parameter.

Accepted Answer

A) True 
 B)False

Question 9

Suppose 1,600 of 2,000 registered voters sampled said they planned to vote for the Republican candidate for president. Using the 0.95 degree of confidence, what is the interval estimate for the population proportion (to the nearest 10th of a percent)?

Accepted Answer

A)  78.2% to 81.8% 
B)  69.2% to 86.4% 
C)  76.5% to 83.5% 
D)  77.7% to 82.3% 
A)  78.2% to 81.8% 
B)  69.2% to 86.4% 
C)  76.5% to 83.5% 
D)  77.7% to 82.3%

Question 10

A group of statistics students decided to conduct a survey at their university to estimate the average (mean) amount of time students spent studying per week. They sampled 554 students and found a mean of 22.3 hours per week. Assuming a population standard deviation of six hours, what is the 95% level of confidence?

Accepted Answer

A)  [21.80, 22.80] 
B)  [16.3, 28.3] 
C)  [21.64, 22.96] 
D)  [20.22, 22.0] 
A)  [21.80, 22.80] 
B)  [16.3, 28.3] 
C)  [21.64, 22.96] 
D)  [20.22, 22.0]

Question 11

A silkscreen printing company purchases t-shirts. To ensure the quality of the shipment, 300 t-shirts are randomly selected. Fifteen are defective. What is the estimated proportion defective in the population?

Accepted Answer

0.05
Explanation: To

Question 12

What is the interpretation of a 96% confidence level?

Accepted Answer

A)  There's a 96% chance that the given interval includes the true value of the population parameter. 
B)  Approximately 96 out of 100 such intervals would include the true value of the population parameter. 
C)  There's a 4% chance that the given interval does not include the true value of the population parameter. 
D)  The interval contains 96% of all sample means. 
A)  There's a 96% chance that the given interval includes the true value of the population parameter. 
B)  Approximately 96 out of 100 such intervals would include the true value of the population parameter. 
C)  There's a 4% chance that the given interval does not include the true value of the population parameter. 
D)  The interval contains 96% of all sample means.

Question 13

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]

Question 14

A research firm wants to compute an interval estimate with 90% confidence for the mean time to complete an employment test. Assuming a population standard deviation of three hours, what is the required sample size if the error should be less than a half hour?

Accepted Answer

A)  196 
B)  98 
C)  10 
D)  16 
A)  196 
B)  98 
C)  10 
D)  16

Question 15

One factor in determining the size of a sample is the degree of confidence selected. This is usually 0.95 or 0.99, but it may be any degree of confidence you specify.

Accepted Answer

A) True 
 B)False

Question 16

The finite population correction factor is used to adjust the z-statistic.

Accepted Answer

A) True 
 B)False

Question 17

Sugar is packaged in 16-ounce bags. If 42 bags are sampled, with a mean of 15.95 ounces and a standard deviation of 0.4 ounces, what is the 99% confidence interval estimate of the population mean?

Accepted Answer

[15.7833, 16.1167]
Explanation

Question 18

A survey of 25 grocery stores revealed that the mean price of a gallon of milk was $2.98, with a standard error of $0.10. If 90% and 95% confidence intervals were developed to estimate the true cost of a gallon of milk, what similarities would they have?

Accepted Answer

A)  Both have the same confidence level 
B)  Both use the same t statistic 
C)  Both use the same z statistic 
D)  Both use the same point estimate of the population mean 
A)  Both have the same confidence level 
B)  Both use the same t statistic 
C)  Both use the same z statistic 
D)  Both use the same point estimate of the population mean

Question 19

For a sampling distribution of means with a known population standard deviation, ______% of the means would be between ±1.96 standard errors.

Accepted Answer

The answer of For a sampling distribution of means with...

Question 20

Approximately 25% of tourists going to Atlantic City to gamble spend more than $500. The Atlantic City Chamber of Commerce wants to update this percentage. For the new study, the estimate should be within 1% of the population proportion, with a 90% confidence level. What is the necessary sample size?

Accepted Answer

5074
Explanation: We use n @#IMG-DLM& Wh

When using the t distribution to calculate a confidence interval, we assume that the population of interest is normal or nearly normal.

A sample of 500 students is selected from a known population of 15000 students to construct a 99% confidence interval for the average SAT score. What correction factor should be used to compute the standard error?

Which of the following is a point estimate for the population mean (µ)?

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.

The population variation has little or no effect in determining the size of a sample selected from the population.

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?

An interval estimate is a single value used to estimate a population parameter.

Suppose 1,600 of 2,000 registered voters sampled said they planned to vote for the Republican candidate for president. Using the 0.95 degree of confidence, what is the interval estimate for the population proportion (to the nearest 10^th of a percent)?

A silkscreen printing company purchases t-shirts. To ensure the quality of the shipment, 300 t-shirts are randomly selected. Fifteen are defective. What is the estimated proportion defective in the population?

What is the interpretation of a 96% confidence level?

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?

A research firm wants to compute an interval estimate with 90% confidence for the mean time to complete an employment test. Assuming a population standard deviation of three hours, what is the required sample size if the error should be less than a half hour?

One factor in determining the size of a sample is the degree of confidence selected. This is usually 0.95 or 0.99, but it may be any degree of confidence you specify.

The finite population correction factor is used to adjust the z-statistic.

Sugar is packaged in 16-ounce bags. If 42 bags are sampled, with a mean of 15.95 ounces and a standard deviation of 0.4 ounces, what is the 99% confidence interval estimate of the population mean?

A survey of 25 grocery stores revealed that the mean price of a gallon of milk was $2.98, with a standard error of $0.10. If 90% and 95% confidence intervals were developed to estimate the true cost of a gallon of milk, what similarities would they have?

For a sampling distribution of means with a known population standard deviation, ______% of the means would be between ±1.96 standard errors.

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 the t distribution to calculate a confidence interval, we assume that the population of interest is normal or nearly normal.

A sample of 500 students is selected from a known population of 15000 students to construct a 99% confidence interval for the average SAT score. What correction factor should be used to compute the standard error?

Which of the following is a point estimate for the population mean (µ)?

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.

The population variation has little or no effect in determining the size of a sample selected from the population.

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?

An interval estimate is a single value used to estimate a population parameter.

Suppose 1,600 of 2,000 registered voters sampled said they planned to vote for the Republican candidate for president. Using the 0.95 degree of confidence, what is the interval estimate for the population proportion (to the nearest 10th of a percent)?

A silkscreen printing company purchases t-shirts. To ensure the quality of the shipment, 300 t-shirts are randomly selected. Fifteen are defective. What is the estimated proportion defective in the population?

What is the interpretation of a 96% confidence level?

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?

A research firm wants to compute an interval estimate with 90% confidence for the mean time to complete an employment test. Assuming a population standard deviation of three hours, what is the required sample size if the error should be less than a half hour?

One factor in determining the size of a sample is the degree of confidence selected. This is usually 0.95 or 0.99, but it may be any degree of confidence you specify.

The finite population correction factor is used to adjust the z-statistic.

Sugar is packaged in 16-ounce bags. If 42 bags are sampled, with a mean of 15.95 ounces and a standard deviation of 0.4 ounces, what is the 99% confidence interval estimate of the population mean?

A survey of 25 grocery stores revealed that the mean price of a gallon of milk was $2.98, with a standard error of $0.10. If 90% and 95% confidence intervals were developed to estimate the true cost of a gallon of milk, what similarities would they have?

For a sampling distribution of means with a known population standard deviation, ______% of the means would be between ±1.96 standard errors.

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

Suppose 1,600 of 2,000 registered voters sampled said they planned to vote for the Republican candidate for president. Using the 0.95 degree of confidence, what is the interval estimate for the population proportion (to the nearest 10^th of a percent)?