The problem with relying on a point estimate of a population parameter is that: $\begin{array}{|l|l|} \hline A&\text {it has no variance. }\\ \hline B&\text { it might be unbiased.}\\ \hline C&\text { it might not be relatively efficient.}\\ \hline D&\text {it does not tell us how close or far the point estimate might be from the parameter. }\\ \hline \end{array}$

The answer of The problem with relying on a point...

Which of the following statistical distributions are used to find a confidence interval for the population proportion? $\begin{array}{|l|l|} \hline A&\text { Student \( t $ distribution}\\ \hline B&\text {Standard normal distribution }\\ \hline C&\text { Chi-square distribution}\\ \hline D&\text { None of these choices are correct.}\\ \hline \end{array}\)

The answer of Which of the following statistical distributions are...

For statistical inference about the mean of a single population when the population standard deviation is unknown, the number of degrees for freedom for the t-distribution is equal to n - 1 because we lose one degree of freedom by using the: $\begin{array}{|l|l|} \hline A&\text { sample mean as an estimate of the population mean.}\\ \hline B&\text {sample standard deviation as an estimate of the population standard deviation. }\\ \hline C&\text {sample proportion as an estimate of the population proportion. }\\ \hline D&\text { sample size as an estimate of the population size.}\\ \hline \end{array}$

The answer of For statistical inference about the mean of...

Which of the following is true about the t-distribution? $\begin{array}{|l|l|} \hline A&\text { It approaches the normal distribution as the number of degrees of freedom increases.}\\ \hline B&\text {It assumes that the population is normally distributed. }\\ \hline C&\text { It is more spread out than the standard normal distribution.}\\ \hline D&\text { All of these choices are correct.}\\ \hline \end{array}$

The answer of Which of the following is true about...

Which of the following is the width of the confidence interval for the population mean? $\begin{array}{|l|l|} \hline A&\text {Upper confidence limit + Lower confidence limit }\\ \hline B&\text {(Upper confidence limit - Lower confidence)/2 }\\ \hline C&\text { Upper confidence limit - Lower confidence limit}\\ \hline D&\text {None of these choices are correct. }\\ \hline \end{array}$

The answer of Which of the following is the width...

Exam 11: Estimation: Describing a Single Population

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should you use, changing the standard deviation to 90?

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Question 81

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should be used if you wish to estimate the population mean to within 5 units?

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Question 82

An interval estimate is an estimate of the range for a population parameter.

(True/False)

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Question 83

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should you use?

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Question 84

The head of the statistics department in a certain university believes that 70% of the department's graduate assistantships are given to international students. A random sample of 50 graduate assistants is taken. a. Assume that the chairman is correct and p = 0.70. What is the sampling distribution of the sample proportion $\hat { p }$ . Explain. b. Find the expected value and the standard error of the sampling distribution of $\hat { p }$ . c. What is the probability that the sample proportion $\hat { p }$ will be between 0.65 and 0.73? d. What is the probability that the sample proportion $\hat { p }$ will be within ±0.05 of the population proportion p?

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Question 85

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should you use, changing the standard deviation to 50?

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Question 86

Suppose that the amount of time teenagers spend on the Internet is normally distributed, with a standard deviation of 1.5 hours. A sample of 100 teenagers is selected at random, and the sample mean is computed as 6.5 hours. Determine the 95% confidence interval estimate of the population mean. Interpret

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Question 87

Determine the minimum sample size required for estimating the population proportion of number of people who drive to work, to within 0.003, with 80% confidence.

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Question 88

The lower and upper limits of the 68.26% confidence interval for the population mean $\mu$ , given that n = 64, $\bar { x }$ = 110 and $\sigma$ = 8, are 109 and 111, respectively.

(True/False)

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Question 89

The problem with relying on a point estimate of a population parameter is that: A it has no variance. B it might be unbiased. C it might not be relatively efficient. D it does not tell us how close or far the point estimate might be from the parameter.

(Short Answer)

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Question 90

Recall the rule of thumb used to indicate when the normal distribution is a good approximation to the sampling distribution for the sample proportion $\hat { p }$ . For the combination n = 50; p = 0.05, the rule is satisfied.

(True/False)

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Question 91

Which of the following statistical distributions are used to find a confidence interval for the population proportion? A Student t distribution B Standard normal distribution C Chi-square distribution D None of these choices are correct.

(Short Answer)

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Question 92

A statistician wants to estimate the mean weekly family expenditure on clothes. He believes that the largest weekly expenditure is $650 and the lowest is $150. a. Estimate the standard deviation of the weekly expenditure. b. Determine with 99% confidence the number of families that must be sampled to estimate the mean weekly family expenditure on clothes to within $15.

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Question 93

What is the margin of error for a 99% confidence interval for the population proportion of people that own more than one mobile phone, if a random sample of 50 people was taken, and 10 of these had more than one mobile phone?

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Question 94

For statistical inference about the mean of a single population when the population standard deviation is unknown, the number of degrees for freedom for the t-distribution is equal to n - 1 because we lose one degree of freedom by using the: A sample mean as an estimate of the population mean. B sample standard deviation as an estimate of the population standard deviation. C sample proportion as an estimate of the population proportion. D sample size as an estimate of the population size.

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Question 95

How large a sample of state employees should be taken if we want to estimate with 98% confidence the mean salary to within $2000. The population standard deviation is assumed to be $10 500.

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Question 96

A politician believes that the proportion of voters who will vote for a Coalition candidate in the 2004 general election is 0.65. A sample of 500 voters is selected at random. a. Assume that the politician is correct and p = 0.65. What is the sampling distribution of the sample proportion $\hat { p }$ ? Explain. b. Find the expected value and standard deviation of the sample proportion $\hat { p }$ . c. What is the probability that the number of voters in the sample who will vote for a Labor candidate in the 2004 general election will be between 340 and 350?

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Question 97

An unbiased estimator of a population parameter is an estimator whose expected value is equal to the population parameter to be estimated.

(True/False)

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Question 98

Which of the following is true about the t-distribution? A It approaches the normal distribution as the number of degrees of freedom increases. B It assumes that the population is normally distributed. C It is more spread out than the standard normal distribution. D All of these choices are correct.

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Question 99

Which of the following is the width of the confidence interval for the population mean? A Upper confidence limit + Lower confidence limit B (Upper confidence limit - Lower confidence)/2 C Upper confidence limit - Lower confidence limit D None of these choices are correct.

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Question 100

Showing 81 - 100 of 132

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should you use, changing the standard deviation to 90?

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should be used if you wish to estimate the population mean to within 5 units?

An interval estimate is an estimate of the range for a population parameter.

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should you use?

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should you use, changing the standard deviation to 50?

Determine the minimum sample size required for estimating the population proportion of number of people who drive to work, to within 0.003, with 80% confidence.

The lower and upper limits of the 68.26% confidence interval for the population mean $\mu$ , given that n = 64, $\bar { x }$ = 110 and $\sigma$ = 8, are 109 and 111, respectively.

The problem with relying on a point estimate of a population parameter is that: A it has no variance. B it might be unbiased. C it might not be relatively efficient. D it does not tell us how close or far the point estimate might be from the parameter.

Recall the rule of thumb used to indicate when the normal distribution is a good approximation to the sampling distribution for the sample proportion $\hat { p }$ . For the combination n = 50; p = 0.05, the rule is satisfied.

Which of the following statistical distributions are used to find a confidence interval for the population proportion? A Student t distribution B Standard normal distribution C Chi-square distribution D None of these choices are correct.

What is the margin of error for a 99% confidence interval for the population proportion of people that own more than one mobile phone, if a random sample of 50 people was taken, and 10 of these had more than one mobile phone?

How large a sample of state employees should be taken if we want to estimate with 98% confidence the mean salary to within $2000. The population standard deviation is assumed to be $10 500.

An unbiased estimator of a population parameter is an estimator whose expected value is equal to the population parameter to be estimated.

Which of the following is true about the t-distribution? A It approaches the normal distribution as the number of degrees of freedom increases. B It assumes that the population is normally distributed. C It is more spread out than the standard normal distribution. D All of these choices are correct.

Which of the following is the width of the confidence interval for the population mean? A Upper confidence limit + Lower confidence limit B (Upper confidence limit - Lower confidence)/2 C Upper confidence limit - Lower confidence limit D None of these choices are correct.

What Is Statistics

Types of Data, Data Collection and Sampling

Graphical Descriptive Methods Nominal Data

Graphical Descriptive Techniques Numerical Data

Numerical Descriptive Measures

Probability

Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Statistical Inference: Introduction

Sampling Distributions

Estimation: Comparing Two Populations

Hypothesis Testing: Describing a Single Population

Hypothesis Testing: Comparing Two Populations

Inference About Population Variances

Analysis of Variance

Additional Tests for Nominal Data: Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Model Building

Nonparametric Techniques

Statistical Inference: Conclusion

Time-Series Analysis and Forecasting

Index Numbers

Decision Analysis

Filters

Exam 11: Estimation: Describing a Single Population

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should you use, changing the standard deviation to 90?

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should be used if you wish to estimate the population mean to within 5 units?

An interval estimate is an estimate of the range for a population parameter.

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should you use?

Suppose that your task is to estimate the mean of a normally distributed population to within 10 units with 95% confidence and that the population standard deviation is known to be 70. What sample size should you use, changing the standard deviation to 50?

Determine the minimum sample size required for estimating the population proportion of number of people who drive to work, to within 0.003, with 80% confidence.

The lower and upper limits of the 68.26% confidence interval for the population mean μ\muμ , given that n = 64, xˉ\bar { x }xˉ = 110 and σ\sigmaσ = 8, are 109 and 111, respectively.

The problem with relying on a point estimate of a population parameter is that: A it has no variance. B it might be unbiased. C it might not be relatively efficient. D it does not tell us how close or far the point estimate might be from the parameter.

Recall the rule of thumb used to indicate when the normal distribution is a good approximation to the sampling distribution for the sample proportion p^\hat { p }p^​ . For the combination n = 50; p = 0.05, the rule is satisfied.

Which of the following statistical distributions are used to find a confidence interval for the population proportion? A Student t distribution B Standard normal distribution C Chi-square distribution D None of these choices are correct.

What is the margin of error for a 99% confidence interval for the population proportion of people that own more than one mobile phone, if a random sample of 50 people was taken, and 10 of these had more than one mobile phone?

How large a sample of state employees should be taken if we want to estimate with 98% confidence the mean salary to within $2000. The population standard deviation is assumed to be $10 500.

An unbiased estimator of a population parameter is an estimator whose expected value is equal to the population parameter to be estimated.

Which of the following is the width of the confidence interval for the population mean? A Upper confidence limit + Lower confidence limit B (Upper confidence limit - Lower confidence)/2 C Upper confidence limit - Lower confidence limit D None of these choices are correct.

What Is Statistics

Types of Data, Data Collection and Sampling

Graphical Descriptive Methods Nominal Data

Graphical Descriptive Techniques Numerical Data

Numerical Descriptive Measures

Probability

Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Statistical Inference: Introduction

Sampling Distributions

Estimation: Comparing Two Populations

Hypothesis Testing: Describing a Single Population

Hypothesis Testing: Comparing Two Populations

Inference About Population Variances

Analysis of Variance

Additional Tests for Nominal Data: Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Model Building

Nonparametric Techniques

Statistical Inference: Conclusion

Time-Series Analysis and Forecasting

Index Numbers

Decision Analysis

Filters

The lower and upper limits of the 68.26% confidence interval for the population mean $\mu$ , given that n = 64, $\bar { x }$ = 110 and $\sigma$ = 8, are 109 and 111, respectively.

Recall the rule of thumb used to indicate when the normal distribution is a good approximation to the sampling distribution for the sample proportion $\hat { p }$ . For the combination n = 50; p = 0.05, the rule is satisfied.