Question 1

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

Accepted Answer

A) True 
 B)False

Question 2

Because the value of the ____________________ varies randomly from sample to sample, we can regard it as a new random variable created by sampling.

Accepted Answer

The answer of Because the value of the ____________________ varies...

Question 3

Two random samples of sizes 30 and 36 are selected independently from two populations with means 80 and 88, and standard deviations 15 and 20, respectively.
a.
Find the standard error of the difference betweenand.
b.
Find the probability that the mean of the first sample is smaller than the mean of the second sample.

Accepted Answer

a.= 4.314
b.
P(< 0) = P(Z < 1.

Question 4

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.

Accepted Answer

The answer of Retirees
A sample of 50 retirees is drawn...

Question 5

The owner of a meat market has an assistant who has determined that the weights of roasts are normally distributed, with a mean of 3.2 pounds and standard deviation of 0.8 pounds.If a sample of 25 roasts yields a mean of 3.6 pounds, what is the Z-score for this sample mean?

Accepted Answer

A)  -2.50 
B)  2.50 
C) -0.50 
D)  None of these choices. 
A)  -2.50 
B)  2.50 
C) -0.50 
D)  None of these choices.

Question 6

Suppose that 100 items are drawn from a population of manufactured products and the weight, X, of each item is recorded.Prior experience has shown that the weight has a non-normal probability distribution with $\mu$ = 8 ounces and$\sigma$ = 3 ounces.Which of the following is true about the sampling of   ?

Accepted Answer

A)  Its mean is 8 ounces. 
B)  Its standard error is 0.3 ounces. 
C)  Its shape is approximately normal. 
D)  All of these choices are true. 
A)  Its mean is 8 ounces. 
B)  Its standard error is 0.3 ounces. 
C)  Its shape is approximately normal. 
D)  All of these choices are true.

Question 7

Mean Salary
In order to estimate the mean salary for a population of 500 employees, the president of a certain company selected at random a sample of 40 employees.
-{Mean Salary Narrative} If the population standard deviation is $800, compute the standard error both with and without using the finite population correction factor.

Accepted Answer

@#IMG-DLM& = $121.448 and $126.491 with

Question 8

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?

Accepted Answer

The answer of Temporary Worker Productivity
A temporary worker productivity is...

Question 9

The expected value of   is ____________________.

Accepted Answer

The answer of The expected value of   is...

Question 10

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?

Accepted Answer

The answer of Retirees
A sample of 50 retirees is drawn...

Question 11

A sample of size n is selected at random from an infinite population.As n increases, the standard error of the sample mean increases.

Accepted Answer

A) True 
 B)False

Question 12

As n gets larger, the sampling distribution of   becomes increasingly bell shaped.This phenomenon is due to the ____________________.

Accepted Answer

Central Li

Question 13

Suppose it is known that 60% of radio listeners at a particular college are smokers.A sample of 500 students from the college is selected at random.Approximate the probability that at least 280 of these students are radio listeners.

Accepted Answer

The answer of Suppose it is known that 60% of...

Question 14

The standard error of the mean:

Accepted Answer

A)  is never larger than the standard deviation of the population. 
B)  decreases as the sample size increases. 
C)  measures the variability of the mean from sample to sample. 
D)  All of these choices are true. 
A)  is never larger than the standard deviation of the population. 
B)  decreases as the sample size increases. 
C)  measures the variability of the mean from sample to sample. 
D)  All of these choices are true.

Question 15

A randomly selected value of   is likely to be ____________________ to(than) the mean of the population than is a randomly selected value of X.

Accepted Answer

The answer of A randomly selected value of  ...

Question 16

Which of the following is true about the sampling distribution of the sample mean?

Accepted Answer

A)  Its mean is always equal to 
B)  Its standard error is always equal to the population standard deviation $\sigma$. 
C)  Its shape is exactly normal if n is large enough. 
D)  None of these choices. 
A)  Its mean is always equal to 
B)  Its standard error is always equal to the population standard deviation $\sigma$. 
C)  Its shape is exactly normal if n is large enough. 
D)  None of these choices.

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

The standard error of the difference between sample means,   , is calculated by the formula   where   is the variance of population i (i = 1, 2).

Accepted Answer

A) True 
 B)False

Question 19

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

Accepted Answer

A) True 
 B)False

Question 20

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:

Accepted Answer

A)  increase the sample size to 200. 
B)  decrease the sample size to 50. 
C)  keep the sample size at 100 and change something else. 
D)  None of these choices. 
A)  increase the sample size to 200. 
B)  decrease the sample size to 50. 
C)  keep the sample size at 100 and change something else. 
D)  None of these choices.

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

Because the value of the ____________________ varies randomly from sample to sample, we can regard it as a new random variable created by sampling.

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.

The owner of a meat market has an assistant who has determined that the weights of roasts are normally distributed, with a mean of 3.2 pounds and standard deviation of 0.8 pounds.If a sample of 25 roasts yields a mean of 3.6 pounds, what is the Z-score for this sample mean?

The expected value of is ____________________.

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?

A sample of size n is selected at random from an infinite population.As n increases, the standard error of the sample mean increases.

As n gets larger, the sampling distribution of becomes increasingly bell shaped.This phenomenon is due to the ____________________.

Suppose it is known that 60% of radio listeners at a particular college are smokers.A sample of 500 students from the college is selected at random.Approximate the probability that at least 280 of these students are radio listeners.

The standard error of the mean:

A randomly selected value of is likely to be ____________________ to(than) the mean of the population than is a randomly selected value of X.

Which of the following is true about the sampling distribution of the sample mean?

The standard error of the difference between sample means, , is calculated by the formula where is the variance of population i (i = 1, 2).

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

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:

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

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

Filters

Exam 9: Sampling Distributions

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

Because the value of the ____________________ varies randomly from sample to sample, we can regard it as a new random variable created by sampling.

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.

The owner of a meat market has an assistant who has determined that the weights of roasts are normally distributed, with a mean of 3.2 pounds and standard deviation of 0.8 pounds.If a sample of 25 roasts yields a mean of 3.6 pounds, what is the Z-score for this sample mean?

The expected value of is ____________________.

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?

A sample of size n is selected at random from an infinite population.As n increases, the standard error of the sample mean increases.

As n gets larger, the sampling distribution of becomes increasingly bell shaped.This phenomenon is due to the ____________________.

Suppose it is known that 60% of radio listeners at a particular college are smokers.A sample of 500 students from the college is selected at random.Approximate the probability that at least 280 of these students are radio listeners.

The standard error of the mean:

A randomly selected value of is likely to be ____________________ to(than) the mean of the population than is a randomly selected value of X.

Which of the following is true about the sampling distribution of the sample mean?

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

The standard error of the difference between sample means, , is calculated by the formula where is the variance of population i (i = 1, 2).

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

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:

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

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

Filters

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