Question 1

If a population is skewed,the point estimate will be pushed to the right or left of the middle of the confidence interval estimate.

Accepted Answer

A) True 
 B)False

Question 2

A random sample of 340 people in Chicago showed that 66 listened to WJKT-1450,a radio station in South Chicago Heights.Based on this information,what is the upper limit for the 95 percent confidence interval estimate for the proportion of people in Chicago that listen to WJKT-1450?

Accepted Answer

A) 1.96 
B) Approximately 0.0009 
C) About 0.2361 
D) About 0.2298 
A) 1.96 
B) Approximately 0.0009 
C) About 0.2361 
D) About 0.2298

Question 3

One way to reduce the margin of error in a confidence interval estimate is to lower the level of confidence.

Accepted Answer

A) True 
 B)False

Question 4

The bottlers of a new fruit juice daily select a random sample of 12 bottles of the drink to estimate the mean quantity of juice in the bottles filled that day.On one such day,the following results were observed:    = 12.03;s = 0.12.Based on this information,the upper limit for a 95 percent confidence interval estimate is approximately 12.106 ounces.

Accepted Answer

A) True 
 B)False

Question 5

Even before the record gas prices during the summer of 2008,an article written by Will Lester of the Associated Press reported on a poll in which 80% of those surveyed say that Americans who currently own a SUV (sport utility vehicle)should switch to a more fuel-efficient vehicle to ease America's dependency on foreign oil.This study was conducted by the Pew Research Center for the People & the Press.As a follow-up to this report,a consumer group conducted a study of SUV owners to estimate the mean mileage for their vehicles.A simple random sample of 91 SUV owners was selected,and the owners were asked to report their highway mileage.The following results were summarized from the sample data:   = 18.2 mpg s = 6.3 mpg
Based on these sample data,compute and interpret a 90% confidence interval estimate for the mean highway mileage for SUVs.

Accepted Answer

A) (15.4,21.0) 
B) (12.4,24.0) 
C) (17.6,18.8) 
D) (17.1,19.3) 
A) (15.4,21.0) 
B) (12.4,24.0) 
C) (17.6,18.8) 
D) (17.1,19.3)

Question 6

Suppose a study estimated the population mean for a variable of interest using a 99% confidence interval.If the width of the estimated confidence interval (the difference between the upper limit and the lower limit)is 600 and the sample size used in estimating the mean is 1,000,what is the population standard deviation?

Accepted Answer

A) 26711.14 
B) 2451.23 
C) 3684.21 
D) 5125.11 
A) 26711.14 
B) 2451.23 
C) 3684.21 
D) 5125.11

Question 7

The following data represent a random sample of bank balances for a population of checking account customers at a large eastern bank.Based on these data,what is the critical value for a 95 percent confidence interval estimate for the true population mean?

Accepted Answer

A) 1.96 
B) 2.1009 
C) 2.1098 
D) None of the above 
A) 1.96 
B) 2.1009 
C) 2.1098 
D) None of the above

Question 8

In developing a confidence interval estimate for the population mean,which of the following is true?

Accepted Answer

A) The larger the sample standard deviation,the wider will be the interval estimate,all other things being equal. 
B) If the population standard deviation is unknown,the appropriate critical value should be obtained from the t-distribution. 
C) The confidence interval developed from a smaller sample size will have a larger margin of error than one obtained using a larger sample size,all other things being equal. 
D) All of the above are true. 
A) The larger the sample standard deviation,the wider will be the interval estimate,all other things being equal. 
B) If the population standard deviation is unknown,the appropriate critical value should be obtained from the t-distribution. 
C) The confidence interval developed from a smaller sample size will have a larger margin of error than one obtained using a larger sample size,all other things being equal. 
D) All of the above are true.

Question 9

A point estimate for the population mean will always fall within the confidence interval estimate.

Accepted Answer

A) True 
 B)False

Question 10

A university computer lab manager wishes to estimate the mean time that students stay in the lab per visit.She believes that the population standard deviation would be no larger than 10 minutes.Further,she wishes to have a confidence level of 90 percent and a margin of error of ±2.00 minutes.Given this,the sample size that she uses is approximately 60 students.

Accepted Answer

A) True 
 B)False

Question 11

The manager of the local county fair believes that no more than 30 percent of the adults in the county would object to a fee increase to attend the fair if it meant that better entertainment could be secured.To estimate the true proportion,he has selected a random sample of 200 adults.The manager will use a 90 percent confidence level.Assuming his assumption about the 30 percent holds,the margin of error for the estimate will be approximately ±.169.

Accepted Answer

A) True 
 B)False

Question 12

A traffic engineer plans to estimate the average number of cars that pass through an intersection each day.Based on previous studies the standard deviation is believed to be 52 cars.She wants to estimate the mean to within ±10 cars with 90 percent confidence.The needed sample size for n is:

Accepted Answer

A) n = 104 days. 
B) n = 74 days. 
C) n = 10 days. 
D) n = 9 days. 
A) n = 104 days. 
B) n = 74 days. 
C) n = 10 days. 
D) n = 9 days.

Question 13

A 95 percent confidence interval estimate indicates that there is a 95 percent chance that the true population value will fall within the range defined by the upper and lower limits.

Accepted Answer

A) True 
 B)False

Question 14

The sampling distribution for a proportion has a formula for that standard error that involves using p.Yet when a confidence interval is calculated for a proportion,the standard error formula uses the sample proportion.Why do they differ?

Accepted Answer

The correct way to calculate the standar

If a population is skewed,the point estimate will be pushed to the right or left of the middle of the confidence interval estimate.

A random sample of 340 people in Chicago showed that 66 listened to WJKT-1450,a radio station in South Chicago Heights.Based on this information,what is the upper limit for the 95 percent confidence interval estimate for the proportion of people in Chicago that listen to WJKT-1450?

One way to reduce the margin of error in a confidence interval estimate is to lower the level of confidence.

The following data represent a random sample of bank balances for a population of checking account customers at a large eastern bank.Based on these data,what is the critical value for a 95 percent confidence interval estimate for the true population mean?

In developing a confidence interval estimate for the population mean,which of the following is true?

A point estimate for the population mean will always fall within the confidence interval estimate.

A traffic engineer plans to estimate the average number of cars that pass through an intersection each day.Based on previous studies the standard deviation is believed to be 52 cars.She wants to estimate the mean to within ±10 cars with 90 percent confidence.The needed sample size for n is:

A 95 percent confidence interval estimate indicates that there is a 95 percent chance that the true population value will fall within the range defined by the upper and lower limits.

The sampling distribution for a proportion has a formula for that standard error that involves using p.Yet when a confidence interval is calculated for a proportion,the standard error formula uses the sample proportion.Why do they differ?

The Where,Why,and How of Data Collection

Graphs,Charts and Tablesdescribing Your Data

Describing Data Using Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Introduction to Continuous Probability Distributions

Introduction to Sampling Distributions

Introduction to Hypothesis Testing

Estimation and Hypothesis Testing for Two Population Parameters

Hypothesis Tests and Estimation for Population Variances

Analysis of Variance

Goodness-Of-Fit Tests and Contingency Analysis

Introduction to Linear Regression and Correlation Analysis

Multiple Regression Analysis and Model Building

Analyzing and Forecasting Time-Series Data

Introduction to Nonparametric Statistics

Introduction to Quality and Statistical Process Control

Filters

Exam 8: Estimating Single Population Parameters

If a population is skewed,the point estimate will be pushed to the right or left of the middle of the confidence interval estimate.

A random sample of 340 people in Chicago showed that 66 listened to WJKT-1450,a radio station in South Chicago Heights.Based on this information,what is the upper limit for the 95 percent confidence interval estimate for the proportion of people in Chicago that listen to WJKT-1450?

One way to reduce the margin of error in a confidence interval estimate is to lower the level of confidence.

The following data represent a random sample of bank balances for a population of checking account customers at a large eastern bank.Based on these data,what is the critical value for a 95 percent confidence interval estimate for the true population mean?

In developing a confidence interval estimate for the population mean,which of the following is true?

A point estimate for the population mean will always fall within the confidence interval estimate.

A traffic engineer plans to estimate the average number of cars that pass through an intersection each day.Based on previous studies the standard deviation is believed to be 52 cars.She wants to estimate the mean to within ±10 cars with 90 percent confidence.The needed sample size for n is:

A 95 percent confidence interval estimate indicates that there is a 95 percent chance that the true population value will fall within the range defined by the upper and lower limits.

The sampling distribution for a proportion has a formula for that standard error that involves using p.Yet when a confidence interval is calculated for a proportion,the standard error formula uses the sample proportion.Why do they differ?

The Where,Why,and How of Data Collection

Graphs,Charts and Tablesdescribing Your Data

Describing Data Using Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Introduction to Continuous Probability Distributions

Introduction to Sampling Distributions

Introduction to Hypothesis Testing

Estimation and Hypothesis Testing for Two Population Parameters

Hypothesis Tests and Estimation for Population Variances

Analysis of Variance

Goodness-Of-Fit Tests and Contingency Analysis

Introduction to Linear Regression and Correlation Analysis

Multiple Regression Analysis and Model Building

Analyzing and Forecasting Time-Series Data

Introduction to Nonparametric Statistics

Introduction to Quality and Statistical Process Control

Filters