Number of Fish Tanks The following data give the number of fish tanks owned for a population of 4 families. \[\begin{array} { | l | c c c c | } \hline \text { Family } & \text { A } & \text { B } & \text { C } & \text { D } \\ \hline \text { Number af Fish Tanks Owned } & 2 & 1 & 4 & 3 \\ \hline \end{array}\] -{Number of Fish Tanks Narrative} List all possible samples of 2 families that can be selected without replacement from this population,and compute the sample mean $\bar { X }$ for each sample.

\[\begin{array} { | c | c c c c c c | }

Exam 9: Sampling Distributions

The finite population correction is not needed if the population size is large relative to the sample size.As a rule of thumb,we will treat any population that is at least ____________________ times larger than the sample size as large.

(Essay)

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Question 61

Suppose the ages of students in your program follow a positively skewed distribution with mean of 24 years and a standard deviation of 4 years.If we randomly sampled 100 students,which of the following statements about the sampling distribution of the sample mean age is NOT true?

(Multiple Choice)

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Question 62

The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed,with a mean of 3.2 pounds and standard deviation of 0.84 pounds.If a sample of 16 fish is taken,what is the standard error of the mean weight?

(Multiple Choice)

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Question 63

If two random samples of sizes 30 and 36 are selected independently from two populations with means 78 and 85,and standard deviations 12 and 15,respectively,then the mean of the difference $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ is equal to:

(Multiple Choice)

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Question 64

As the size of the sample is increased,the standard error of $\bar { X }$ decreases.

(True/False)

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Question 65

CFO's Salary Suppose that the starting salaries of female CFO's have a positively skewed distribution with mean of $56,000 and a standard deviation of $12,000.The starting salaries of male CFO's are positively skewed with a mean of $50,000 and a standard deviation of $10,000.A random sample of 50 female CFO's and a random sample of 40 male CFO's are selected. -{CFO's Salary Narrative} What is the sampling distribution of the sample mean difference $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ ? Explain.

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Question 66

Magazines A local magazine store sells an average of 2,100 magazines per day,with a standard deviation of 500 magazines.Consider a sample of 60 days of operation. -{Magazines Narrative} What is the shape of the sampling distribution of the sample mean number of magazines sold per day? Why?

(Essay)

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Question 67

Number of Fish Tanks The following data give the number of fish tanks owned for a population of 4 families. Family A B C D Number af Fish Tanks Owned 2 1 4 3 -{Number of Fish Tanks Narrative} List all possible samples of 2 families that can be selected without replacement from this population,and compute the sample mean $\bar { X }$ for each sample.

(Essay)

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Question 68

Retirees A sample of 50 retirees is drawn at random from a normal population whose mean age and standard deviation are 75 and 6 years,respectively. -{Retirees Narrative} What is the probability that the mean age is at most 73 years?

(Essay)

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Question 69

Heights of Fences Heights of fences are normally distributed with a mean of 52 inches and a standard deviation of 4 inches. -{Heights of Fences Narrative} Find the probability that one randomly selected fence is under 54 inches.

(Essay)

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Question 70

Magazines A local magazine store sells an average of 2,100 magazines per day,with a standard deviation of 500 magazines.Consider a sample of 60 days of operation. -{Magazines Narrative} Find the expected value and the standard error of the sample mean.

(Essay)

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Question 71

In general,the binomial probability P(X $\le$ x)is approximated by the area under the normal curve to the left of x + .5.

(True/False)

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Question 72

College Dean A college dean would like to estimate a population mean to within 40 units with 99% confidence given that the population standard deviation is 200. -Consider an infinite population with a mean of 100 and a standard deviation of 20.A random sample of size 64 is taken from this population.The standard deviation of the sample mean equals 2.50.

(True/False)

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Question 73

Barack Obama Bill Clinton,the former President of the United States,believes that the proportion of voters who will vote for Barack Obama in the year 2012 presidential elections is 0.65.A sample of 500 voters is selected at random. -{Barack Obama Narrative} What is the probability that the number of voters in the sample who will vote for Barack Obama in the year 2012 is between 340 and 350?

(Essay)

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Question 74

Retirees A sample of 50 retirees is drawn at random from a normal population whose mean age and standard deviation are 75 and 6 years,respectively. -(Retirees Narrative} Find the mean and standard error of the sampling distribution of the sample mean.

(Essay)

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Question 75

If two random samples of sizes 30 and 36 are selected independently from two populations with means 78 and 85,and standard deviations 12 and 15,respectively,then the standard error of the difference $\bar { X } _ { 1 }$ and $\bar { X } _ { 2 }$ is equal to:

(Multiple Choice)

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Question 76

Consider an infinite population with a mean of 160 and a standard deviation of 25.A random sample of size 64 is taken from this population.The standard deviation of the sample mean equals:

(Multiple Choice)

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Question 77

The standard deviation of $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ is also called the:

(Multiple Choice)

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Question 78

A CPA knows from past history that the average accounts receivable for a company is $521.72 with a standard deviation of $584.64.If the auditor takes a simple random sample of 100 accounts,what is the probability that the mean of the sample is within $120 of the population mean?

(Essay)

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Question 79

College Dean A college dean would like to estimate a population mean to within 40 units with 99% confidence given that the population standard deviation is 200. -A sample of size n is selected at random from an infinite population.As n increases,the standard error of the sample mean increases.

(True/False)

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Question 80

Showing 61 - 80 of 150

Exam 9: Sampling Distributions

The finite population correction is not needed if the population size is large relative to the sample size.As a rule of thumb,we will treat any population that is at least ____________________ times larger than the sample size as large.

Suppose the ages of students in your program follow a positively skewed distribution with mean of 24 years and a standard deviation of 4 years.If we randomly sampled 100 students,which of the following statements about the sampling distribution of the sample mean age is NOT true?

The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed,with a mean of 3.2 pounds and standard deviation of 0.84 pounds.If a sample of 16 fish is taken,what is the standard error of the mean weight?

If two random samples of sizes 30 and 36 are selected independently from two populations with means 78 and 85,and standard deviations 12 and 15,respectively,then the mean of the difference Xˉ1−Xˉ2\bar { X } _ { 1 } - \bar { X } _ { 2 }Xˉ1​−Xˉ2​ is equal to:

As the size of the sample is increased,the standard error of Xˉ\bar { X }Xˉ decreases.

Magazines A local magazine store sells an average of 2,100 magazines per day,with a standard deviation of 500 magazines.Consider a sample of 60 days of operation. -{Magazines Narrative} What is the shape of the sampling distribution of the sample mean number of magazines sold per day? Why?

Retirees A sample of 50 retirees is drawn at random from a normal population whose mean age and standard deviation are 75 and 6 years,respectively. -{Retirees Narrative} What is the probability that the mean age is at most 73 years?

Heights of Fences Heights of fences are normally distributed with a mean of 52 inches and a standard deviation of 4 inches. -{Heights of Fences Narrative} Find the probability that one randomly selected fence is under 54 inches.

Magazines A local magazine store sells an average of 2,100 magazines per day,with a standard deviation of 500 magazines.Consider a sample of 60 days of operation. -{Magazines Narrative} Find the expected value and the standard error of the sample mean.

In general,the binomial probability P(X ≤\le≤ x)is approximated by the area under the normal curve to the left of x + .5.

Retirees A sample of 50 retirees is drawn at random from a normal population whose mean age and standard deviation are 75 and 6 years,respectively. -(Retirees Narrative} Find the mean and standard error of the sampling distribution of the sample mean.

If two random samples of sizes 30 and 36 are selected independently from two populations with means 78 and 85,and standard deviations 12 and 15,respectively,then the standard error of the difference Xˉ1\bar { X } _ { 1 }Xˉ1​ and Xˉ2\bar { X } _ { 2 }Xˉ2​ is equal to:

Consider an infinite population with a mean of 160 and a standard deviation of 25.A random sample of size 64 is taken from this population.The standard deviation of the sample mean equals:

The standard deviation of Xˉ1−Xˉ2\bar { X } _ { 1 } - \bar { X } _ { 2 }Xˉ1​−Xˉ2​ is also called the:

A CPA knows from past history that the average accounts receivable for a company is $521.72 with a standard deviation of $584.64.If the auditor takes a simple random sample of 100 accounts,what is the probability that the mean of the sample is within $120 of the population mean?

College Dean A college dean would like to estimate a population mean to within 40 units with 99% confidence given that the population standard deviation is 200. -A sample of size n is selected at random from an infinite population.As n increases,the standard error of the sample mean increases.

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

A: Numerical Descriptive Techniques

B: Numerical Descriptive Techniques

C: Numerical Descriptive Techniques

Data Collection and Sampling

Probability

A: Random Variables and Discrete Probability Distributions

B: Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About a Population

Inference About Comparing Two Populations

Analysis of Variance

Chi-Squared Tests

A: Simple Linear Regression and Correlation

B: Simple Linear Regression and Correlation

Multiple Regression

Model Building

Nonparametric Statistics

Time-Series Analysis and Forecasting

Statistical Process Control

Decision Analysis

Conclusion

Filters

If two random samples of sizes 30 and 36 are selected independently from two populations with means 78 and 85,and standard deviations 12 and 15,respectively,then the mean of the difference $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ is equal to:

As the size of the sample is increased,the standard error of $\bar { X }$ decreases.

In general,the binomial probability P(X $\le$ x)is approximated by the area under the normal curve to the left of x + .5.

If two random samples of sizes 30 and 36 are selected independently from two populations with means 78 and 85,and standard deviations 12 and 15,respectively,then the standard error of the difference $\bar { X } _ { 1 }$ and $\bar { X } _ { 2 }$ is equal to:

The standard deviation of $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ is also called the: