Exam 8: Interval Estimation

The manager of a grocery store has taken a random sample of 144 customers.The average length of time it took these 144 customers to check out was 3 minutes.It is known that the standard deviation of the population of checkout times is 1 minute.The 95% confidence interval for the true average checkout time (in minutes) is

(Multiple Choice)

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Question 21

We can use the normal distribution to make confidence interval estimates for the population proportion, p, when

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Question 22

You are given the following information obtained from a random sample of 5 observations taken from a large population. Construct a 95% confidence interval for the mean of the population, assuming the population has a normal distribution.

(Short Answer)

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Question 23

A random sample of 53 observations was taken.The average in the sample was 90 with a variance of 400. a. Construct a 98% confidence interval for μ. b. Construct a 99% confidence interval for μ. c. Discuss why the 98% and 99% confidence intervals are different. d. What would you expect to happen to the confidence interval in Part a if the sample size was increased? Be sure to explain your answer.

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Question 24

For a given confidence level and when σ is known, the margin of error in a confidence interval estimate

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Question 25

In order to estimate the average electric usage per month, a sample of 64 houses was selected and the electric usage was determined.Assume a population standard deviation of 320 kilowatt-hours.The standard error of the mean is

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Question 26

You are given the following information obtained from a random sample of 6 observations.Assume the population has a normal distribution. a. What is the point estimate of μ? b. Construct an 80% confidence interval for μ. c. Construct a 98% confidence interval for μ. d. Discuss why the 80% and 98% confidence intervals are different.

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Question 27

The makers of a soft drink want to identify the average age of its consumers.A sample of 55 consumers was taken.The average age in the sample was 21 years with a standard deviation of 4 years. a. Construct a 95% confidence interval for the true average age of the consumers. b. Construct an 80% confidence interval for the true average age of the consumers. c. Discuss why the 95% and 80% confidence intervals are different.

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Question 28

A random sample of 100,000 credit sales in a department store showed an average sale of $87.25.From past data, it is known that the standard deviation of the population is $20.00.What is the 95% confidence interval of the population mean?

(Multiple Choice)

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Question 29

Potential sampling error _____as the sample size increases.

(Multiple Choice)

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Question 30

A simple random sample of 144 items resulted in a sample mean of 1257.85 and a standard deviation of 480.Develop a 95% confidence interval for the population mean.

(Short Answer)

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Question 31

From a population that is not normally distributed and whose standard deviation is not known, a sample of 6 items is selected to develop an interval estimate for the mean of the population (μ).

(Multiple Choice)

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Question 32

A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.The margin of error at 95% confidence is

(Multiple Choice)

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Question 33

In interval estimation, as the sample size becomes larger, the interval estimate

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Question 34

A random sample of 100,000 credit sales in a department store showed an average sale of $87.25.From past data, it is known that the standard deviation of the population is $20.00.With a .95 probability, determine the margin of error.

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Question 35

The technical support department at Apple, Inc.sampled 100,000 calls and reported that the mean of time a customer is placed on hold is 4.5 minutes.Assume a standard deviation of 1.75 minutes.Provide a 95% confidence interval estimate for the true average time a customer was placed on hold.

(Short Answer)

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Question 36

In order to determine the average weight of carry-on luggage by passengers in airplanes, a sample of 16 pieces of carry-on luggage was weighed.The average weight was 20 pounds.Assume that we know the standard deviation of the population to be 8 pounds.Also, assume the population is normally distributed. a. Determine a 97% confidence interval estimate for the population mean weight of the carry-on luggage. b. Determine a 95% confidence interval estimate for the population mean weight of the carry-on luggage.

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Question 37

The dean of a college wants to determine the proportion of students who do not use the campus library.What sample size should he take so that, at 97% confidence, the margin of error will not be more than .1?

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Question 38

The probability that the interval estimation procedure will generate an interval that does not contain the actual value of the population parameter being estimated is the

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Question 39

The mean of the t distribution is

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Question 40

Showing 21 - 40 of 144

We can use the normal distribution to make confidence interval estimates for the population proportion, p, when

You are given the following information obtained from a random sample of 5 observations taken from a large population. Construct a 95% confidence interval for the mean of the population, assuming the population has a normal distribution.

For a given confidence level and when σ is known, the margin of error in a confidence interval estimate

In order to estimate the average electric usage per month, a sample of 64 houses was selected and the electric usage was determined.Assume a population standard deviation of 320 kilowatt-hours.The standard error of the mean is

A random sample of 100,000 credit sales in a department store showed an average sale of $87.25.From past data, it is known that the standard deviation of the population is $20.00.What is the 95% confidence interval of the population mean?

Potential sampling error _____as the sample size increases.

A simple random sample of 144 items resulted in a sample mean of 1257.85 and a standard deviation of 480.Develop a 95% confidence interval for the population mean.

From a population that is not normally distributed and whose standard deviation is not known, a sample of 6 items is selected to develop an interval estimate for the mean of the population (μ).

A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.The margin of error at 95% confidence is

In interval estimation, as the sample size becomes larger, the interval estimate

A random sample of 100,000 credit sales in a department store showed an average sale of $87.25.From past data, it is known that the standard deviation of the population is $20.00.With a .95 probability, determine the margin of error.

The technical support department at Apple, Inc.sampled 100,000 calls and reported that the mean of time a customer is placed on hold is 4.5 minutes.Assume a standard deviation of 1.75 minutes.Provide a 95% confidence interval estimate for the true average time a customer was placed on hold.

The dean of a college wants to determine the proportion of students who do not use the campus library.What sample size should he take so that, at 97% confidence, the margin of error will not be more than .1?

The probability that the interval estimation procedure will generate an interval that does not contain the actual value of the population parameter being estimated is the

The mean of the t distribution is

Data and Statistics

Descriptive Statistics: Tabular and Graphical Displays

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Hypothesis Tests

Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Comparing Multiple Proportions, Tests of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

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Exam 8: Interval Estimation

We can use the normal distribution to make confidence interval estimates for the population proportion, p, when​

You are given the following information obtained from a random sample of 5 observations taken from a large population. ​ Construct a 95% confidence interval for the mean of the population, assuming the population has a normal distribution.

For a given confidence level and when σ is known, the margin of error in a confidence interval estimate

In order to estimate the average electric usage per month, a sample of 64 houses was selected and the electric usage was determined.Assume a population standard deviation of 320 kilowatt-hours.The standard error of the mean is

A random sample of 100,000 credit sales in a department store showed an average sale of $87.25.From past data, it is known that the standard deviation of the population is $20.00.What is the 95% confidence interval of the population mean?

Potential sampling error _____as the sample size increases.

A simple random sample of 144 items resulted in a sample mean of 1257.85 and a standard deviation of 480.Develop a 95% confidence interval for the population mean.

From a population that is not normally distributed and whose standard deviation is not known, a sample of 6 items is selected to develop an interval estimate for the mean of the population (μ).

A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.The margin of error at 95% confidence is

In interval estimation, as the sample size becomes larger, the interval estimate

A random sample of 100,000 credit sales in a department store showed an average sale of $87.25.From past data, it is known that the standard deviation of the population is $20.00.With a .95 probability, determine the margin of error.

The technical support department at Apple, Inc.sampled 100,000 calls and reported that the mean of time a customer is placed on hold is 4.5 minutes.Assume a standard deviation of 1.75 minutes.Provide a 95% confidence interval estimate for the true average time a customer was placed on hold.

The dean of a college wants to determine the proportion of students who do not use the campus library.What sample size should he take so that, at 97% confidence, the margin of error will not be more than .1?

The probability that the interval estimation procedure will generate an interval that does not contain the actual value of the population parameter being estimated is the​

The mean of the t distribution is​

Data and Statistics

Descriptive Statistics: Tabular and Graphical Displays

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Hypothesis Tests

Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Comparing Multiple Proportions, Tests of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Filters

We can use the normal distribution to make confidence interval estimates for the population proportion, p, when

You are given the following information obtained from a random sample of 5 observations taken from a large population. Construct a 95% confidence interval for the mean of the population, assuming the population has a normal distribution.

The probability that the interval estimation procedure will generate an interval that does not contain the actual value of the population parameter being estimated is the

The mean of the t distribution is