Question 1

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

Accepted Answer

A) The population standard deviation decreases. 
B) The standard error of the sample mean decreases. 
C) The population standard deviation increases. 
D) The standard error of the sample mean increases. 
A) The population standard deviation decreases. 
B) The standard error of the sample mean decreases. 
C) The population standard deviation increases. 
D) The standard error of the sample mean increases.

Question 2

As a general rule,the normal distribution is used to approximate the sampling distribution of the sample proportion only if:

Accepted Answer

A) the sample size n is greater than 30. 
B) the population proportion p is close to 0.50. 
C) the underlying population is normal. 
D) np and n(1 − p)are both greater than or equal to 5. 
A) the sample size n is greater than 30. 
B) the population proportion p is close to 0.50. 
C) the underlying population is normal. 
D) np and n(1 − p)are both greater than or equal to 5.

Question 3

If all possible samples of size n are drawn from a normal population,the probability distribution of the sample mean   is an normal distribution.

Accepted Answer

A) True 
 B)False

Question 4

As a general rule,the normal distribution is used to approximate the sampling distribution of the sample proportion only if the sample size n is greater than or equal to 30.

Accepted Answer

A) True 
 B)False

Question 5

If all possible samples of size n are drawn from an infinite population with a mean of 15 and a standard deviation of 5,then the standard error of the sample mean equals 1.0 for samples of size:

Accepted Answer

A) 5 
B) 15 
C) 25 
D) None of these choices. 
A) 5 
B) 15 
C) 25 
D) None of these choices.

Question 6

If the sample size increases,the standard error of the mean also increases.

Accepted Answer

A) True 
 B)False

Question 7

The expected value of the sampling distribution of the sample mean   equals the population mean μ :

Accepted Answer

A) only when the population is normally distributed. 
B) only when the sample size is large. 
C) only when the population is infinite. 
D) for all populations. 
A) only when the population is normally distributed. 
B) only when the sample size is large. 
C) only when the population is infinite. 
D) for all populations.

Question 8

The standard error of the sample proportion gets larger as:

Accepted Answer

A) p approaches 0 
B) p approaches 0.50 
C) p approaches 1.00 
D) None of these choices. 
A) p approaches 0 
B) p approaches 0.50 
C) p approaches 1.00 
D) None of these choices.

Question 9

The expected value of the sampling distribution of   where μi is the mean of population i (i = 1,2).

Accepted Answer

A) True 
 B)False

Question 10

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

Accepted Answer

The answer of To find the binomial probability P(X ≤...

Question 11

As n gets ____________________,the shape of the sampling distribution of   becomes increasingly bell shaped.

Accepted Answer

The answer of As n gets ____________________,the shape of the...

Question 12

As a general rule in computing the standard error of the sample mean,the finite population correction factor is used only if the:

Accepted Answer

A) sample size is smaller than 5% of the population size. 
B) sample size is greater than 5% of the sample size. 
C) sample size is more than half of the population size. 
D) None of these choices. 
A) sample size is smaller than 5% of the population size. 
B) sample size is greater than 5% of the sample size. 
C) sample size is more than half of the population size. 
D) None of these choices.

Question 13

When a great many simple random samples of size n are drawn from a population that is normally distributed,the sampling distribution of the sample mean is normal regardless of the sample size n.

Accepted Answer

A) True 
 B)False

Question 14

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,   ,is

Accepted Answer

A) always non-normal 
B) always normal 
C) approximately normal only if n1 and n2 are both larger than or equal to 30 
D) approximately normal regardless of n1 and n2 
A) always non-normal 
B) always normal 
C) approximately normal only if n1 and n2 are both larger than or equal to 30 
D) approximately normal regardless of n1 and n2

Question 15

Which of the following statements about the sampling distribution of   is NOT true?

Accepted Answer

A) It is generated by taking all possible samples of size n and computing their sample means. 
B) Its mean is equal to the population mean μ. 
C) Its standard deviation is equal to the population standard deviation σ. 
D) All of these choices are true. 
A) It is generated by taking all possible samples of size n and computing their sample means. 
B) Its mean is equal to the population mean μ. 
C) Its standard deviation is equal to the population standard deviation σ. 
D) All of these choices are true.

Question 16

Random samples of size 49 are taken from an infinite population whose mean is 300 and standard deviation is 21.The mean and standard error of the sample mean,respectively,are:

Accepted Answer

A) 300 and 21 
B) 300 and 3 
C) 300 and 0.43 
D) None of these choices. 
A) 300 and 21 
B) 300 and 3 
C) 300 and 0.43 
D) None of these choices.

Question 17

Given a binomial random variable with n = 15 and p = .40,find the exact probabilities of the following events and their normal approximations.
a.X = 6
b.X ≥ 9
c.X ≤ 10

Accepted Answer

a. Exact and approximated probabilities

Question 18

Under certain conditions where n is large enough,you can approximate the ____________________ distribution using the ____________________ distribution.

Accepted Answer

The answer of Under certain conditions where n is large...

Question 19

Number of Fish Tanks 
The following data give the number of fish tanks owned for a population of 4 families.   ​ ​
-{Number of Fish Tanks Narrative} A sample of size 2 is drawn at random from the population.Use the formulas   and   to calculate the mean and the standard deviation of the sampling distribution of the sample means.
​

Accepted Answer

The answer of  Number of Fish Tanks 
The following...

Question 20

If the population is normal,then   is normally distributed for __________________ values of n.

Accepted Answer

The answer of If the population is normal,then  ...

Exam 9: Sampling Distributions

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

As a general rule,the normal distribution is used to approximate the sampling distribution of the sample proportion only if:

If all possible samples of size n are drawn from a normal population,the probability distribution of the sample mean is an normal distribution.

As a general rule,the normal distribution is used to approximate the sampling distribution of the sample proportion only if the sample size n is greater than or equal to 30.

If all possible samples of size n are drawn from an infinite population with a mean of 15 and a standard deviation of 5,then the standard error of the sample mean equals 1.0 for samples of size:

If the sample size increases,the standard error of the mean also increases.

The expected value of the sampling distribution of the sample mean equals the population mean μ :

The standard error of the sample proportion gets larger as:

The expected value of the sampling distribution of where μi is the mean of population i (i = 1,2).

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

As n gets ____________________,the shape of the sampling distribution of becomes increasingly bell shaped.

As a general rule in computing the standard error of the sample mean,the finite population correction factor is used only if the:

When a great many simple random samples of size n are drawn from a population that is normally distributed,the sampling distribution of the sample mean is normal regardless of the sample size n.

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, ,is

Which of the following statements about the sampling distribution of is NOT true?

Random samples of size 49 are taken from an infinite population whose mean is 300 and standard deviation is 21.The mean and standard error of the sample mean,respectively,are:

Given a binomial random variable with n = 15 and p = .40,find the exact probabilities of the following events and their normal approximations. a.X = 6 b.X ≥ 9 c.X ≤ 10

Under certain conditions where n is large enough,you can approximate the ____________________ distribution using the ____________________ distribution.

If the population is normal,then is normally distributed for __________________ values of n.

What Is Statistics

Graphical Descriptive Techniques 1

Graphical Descriptive Techniques 2

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

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

Simple Linear Regression and Correlation

Multiple Regression

Model Building

Nonparametric Statistics

Time-Series Analytics and Forecasting

Statistical Process Control

Decision Analysis

Conclusion

Filters

The expected value of the sampling distribution of where μ_i is the mean of population i (i = 1,2).

To find the binomial probability P(X ≤ 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, ,is

Under certain conditions where n is large enough,you can approximate the distribution using the distribution.