Exam 9: Sampling Distributions

Graduate Internships The chairman of the Biology department in a certain college believes that 70% of the department's graduate internships are given to international students.A random sample of 50 graduate interns is taken. -{Graduate Internships Narrative} Find the expected value and the standard error of the sampling distribution of $\hat { p }$ .

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Question 81

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} Find the standard error of the sample mean difference.

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Question 82

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} Find the expected value of the sample mean difference.

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Question 83

For sample sizes greater than 30,the sampling distribution of the mean is approximately normally distributed:

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Question 84

Heights of Men The heights of men in the USA are normally distributed with a mean of 68 inches and a standard deviation of 4 inches. -{Heights of Men Narrative} If the population of men's heights is not normally distributed,which,if any,of the previous questions can you answer?

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Question 85

Average Annual Revenue Suppose that the average annual revenue of a small business is $150,000 with a standard deviation of $40,000.Assume that the revenue distribution is normal. -{Average Annual Revenue Narrative} Could you have used a normal distribution to find an (approximate)probability for the average of 4 revenues if the population of revenues did not have a normal distribution?

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Question 86

The accuracy of the approximation of $\bar { X }$ with a normal distribution depends on the probability distribution of the and on the sample .

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Question 87

The expected value of $\hat { p }$ is ____________________.

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Question 88

To find the binomial probability P(X $\le$ 4)we calculate the area under the normal curve to the (left/right)of the number .

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Question 89

The expected value of the sampling distribution of $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ is $\mu _ { \bar { x } _ { 1 } - \bar { x } _ { 2 } } = \mu _ { 1 } - \mu _ { 2 }$ where $\mu$ _i is the mean of population i (i = 1,2).

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Question 90

In an effort to identify the true proportion of college freshman who are under 18 years of age,a random sample of 500 freshmen was taken.Fifty of them were under the age of 18.The value 0.10 is a point estimate of the true proportion of freshman under age 18.

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Question 91

Temporary Worker Productivity A temporary worker productivity is normally distributed.One worker produces an average of 84 units per day with a standard deviation of 24.Another worker produces at an average rate of 74 per day with a standard deviation of 25. -{Temporary Worker Productivity Narrative} What is the probability that in any single day worker 1 will outproduce worker 2?

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Question 92

A sample of size n is selected at random from an infinite population.As n increases,which of the following statements is true?

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Question 93

The standard error of the mean for a sample of 100 is 25.In order to cut the standard error of the mean in half (to 12.5)we must:

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Question 94

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 probability that the sample mean is between 2,000 and 2,300 magazines?

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Question 95

Sampling distributions describe the distributions of:

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Question 96

If two random samples of sizes n₁ and n₂ are selected independently from two non-normally distributed populations,then the sampling distribution of the sample mean difference, $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ ,is

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Question 97

The standard deviation of the sampling distribution of $\bar { X }$ is also called the:

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Question 98

The mean of the difference $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ is equal to the mean of the difference $\bar { X } _ { 2 } - \bar { X } _ { 1 }$ .

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Question 99

Heights of Men The heights of men in the USA are normally distributed with a mean of 68 inches and a standard deviation of 4 inches. -{Heights of Men Narrative} What is the probability that a randomly selected man is taller than 70 inches?

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Question 100

Showing 81 - 100 of 150

Exam 9: Sampling Distributions

For sample sizes greater than 30,the sampling distribution of the mean is approximately normally distributed:

Heights of Men The heights of men in the USA are normally distributed with a mean of 68 inches and a standard deviation of 4 inches. -{Heights of Men Narrative} If the population of men's heights is not normally distributed,which,if any,of the previous questions can you answer?

The accuracy of the approximation of Xˉ\bar { X }Xˉ with a normal distribution depends on the probability distribution of the ____________________ and on the sample ____________________.

The expected value of p^\hat { p }p^​ is ____________________.

To find the binomial probability P(X ≤\le≤ 4)we calculate the area under the normal curve to the ____________________ (left/right)of the number ____________________.

In an effort to identify the true proportion of college freshman who are under 18 years of age,a random sample of 500 freshmen was taken.Fifty of them were under the age of 18.The value 0.10 is a point estimate of the true proportion of freshman under age 18.

A sample of size n is selected at random from an infinite population.As n increases,which of the following statements is true?

The standard error of the mean for a sample of 100 is 25.In order to cut the standard error of the mean in half (to 12.5)we must:

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 probability that the sample mean is between 2,000 and 2,300 magazines?

Sampling distributions describe the distributions of:

If two random samples of sizes n1 and n2 are selected independently from two non-normally distributed populations,then the sampling distribution of the sample mean difference, Xˉ1−Xˉ2\bar { X } _ { 1 } - \bar { X } _ { 2 }Xˉ1​−Xˉ2​ ,is

The standard deviation of the sampling distribution of Xˉ\bar { X }Xˉ is also called the:

The mean of the difference Xˉ1−Xˉ2\bar { X } _ { 1 } - \bar { X } _ { 2 }Xˉ1​−Xˉ2​ is equal to the mean of the difference Xˉ2−Xˉ1\bar { X } _ { 2 } - \bar { X } _ { 1 }Xˉ2​−Xˉ1​ .

Heights of Men The heights of men in the USA are normally distributed with a mean of 68 inches and a standard deviation of 4 inches. -{Heights of Men Narrative} What is the probability that a randomly selected man is taller than 70 inches?

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

The accuracy of the approximation of $\bar { X }$ with a normal distribution depends on the probability distribution of the and on the sample .

The expected value of $\hat { p }$ is ____________________.

To find the binomial probability P(X $\le$ 4)we calculate the area under the normal curve to the (left/right)of the number .

If two random samples of sizes n₁ and n₂ are selected independently from two non-normally distributed populations,then the sampling distribution of the sample mean difference, $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ ,is

The standard deviation of the sampling distribution of $\bar { X }$ is also called the:

The mean of the difference $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ is equal to the mean of the difference $\bar { X } _ { 2 } - \bar { X } _ { 1 }$ .