Question 1

A sample of size 25 provides a sample variance of 400.The standard error,in this case equal to 4,is best described as the estimate of the standard deviation of means calculated from samples of size 25.

Accepted Answer

A) True 
 B)False

Question 2

TABLE 7-5
According to a survey,only 15% of customers who visited the website of a major retail store made a purchase.Random samples of size 50 are selected.
-Referring to Table 7-5,what proportion of the samples will have less than 15% of customers who will make a purchase after visiting the website?

Accepted Answer

The answer of TABLE 7-5
According to a survey,only 15% of...

Question 3

TABLE 7-5
According to a survey,only 15% of customers who visited the website of a major retail store made a purchase.Random samples of size 50 are selected.
-A study at a college in the west coast reveals that,historically,45% of the students are minority students.If a random sample of size 75 is selected,the probability is ________ that between 30% and 50% of the students in the sample will be minority students.

Accepted Answer

The answer of TABLE 7-5
According to a survey,only 15% of...

Question 4

The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed,with mean of 3.2 pounds and standard deviation of 0.8 pound.What percentage of samples of 4 fish will have sample means between 3.0 and 4.0 pounds?

Accepted Answer

A) 84% 
B) 67% 
C) 29% 
D) 16%

Question 5

The sample mean is an unbiased estimate of the population mean.

Accepted Answer

A) True 
 B)False

Question 6

Assume that house prices in a neighborhood are normally distributed with a standard deviation of $20,000.A random sample of 16 observations is taken.What is the probability that the sample mean differs from the population mean by more than $5,000?

Accepted Answer

The answer of Assume that house prices in a neighborhood...

Question 7

When dealing with human surveys,we are usually interested in sampling with replacement.

Accepted Answer

A) True 
 B)False

Question 8

The Central Limit Theorem is important in statistics because

Accepted Answer

A) for a large n,it says the population is approximately normal. 
B) for any population,it says the sampling distribution of the sample mean is approximately normal,regardless of the sample size. 
C) for a large n,it says the sampling distribution of the sample mean is approximately normal,regardless of the shape of the population. 
D) for any sized sample,it says the sampling distribution of the sample mean is approximately normal.

Question 9

If the amount of gasoline purchased per car at a large service station has a population mean of 15 gallons and a population standard deviation of 4 gallons,then 99.73% of all cars will purchase between 3 and 27 gallons.

Accepted Answer

A) True 
 B)False

Question 10

Coverage error results in a ________.

Accepted Answer

The answer of Coverage error results in a ________....

Question 11

To find out the potential impact of a new zoning law on a neighborhood,the legislators conduct a focus group interview by inviting the members of the housing owners association of that neighborhood.This is an example of a

Accepted Answer

A) systematic sample. 
B) simple random sample. 
C) judgment sample. 
D) cluster sample.

Question 12

Items or individuals in a judgment sample are chosen according to their probability of occurrence.

Accepted Answer

A) True 
 B)False

Question 13

________ results from the exclusion of certain groups of subjects from a population frame.

Accepted Answer

The answer of ________ results from the exclusion of certain...

Question 14

If the population distribution is symmetric,the sampling distribution of the mean can be approximated by the normal distribution if the samples contain 15 observations.

Accepted Answer

A) True 
 B)False

Question 15

Which of the following yields a simple random sample?

Accepted Answer

A) All students in a class are grouped according to their gender.A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females. 
B) The best 15 students,according to the opinion of the instructor,in a class are selected. 
C) The names of 50 students in a class are written on 50 different pieces of paper and put in a hat.The first 15 pieces of paper are selected blindly one at a time after shuffling the papers thoroughly and each of the selected pieces is placed back into the hat before the next piece is selected. 
D) All students in a class are divided into groups according to the rows that they are seated.One of the groups is randomly selected.

Question 16

At US Data Corporation's website,they advertised that "Because of our commitment to quality and our vast amount of industry knowledge and experience,we have grown to be one of America's leading providers of mailing lists,marketing data,sales leads and research data.We maintain databases of information on consumers and businesses nationwide that set industry standards for mission critical currency,reliability and accuracy." Trying to reach 500 potential donors for their annual phone donation campaign,a local fire department purchased a list of donors from the company.This list is an example of a

Accepted Answer

A) population. 
B) statistic. 
C) parameter. 
D) frame.

Question 17

The only way one can eliminate sampling error is to take the whole population as the sample.

Accepted Answer

A) True 
 B)False

Question 18

TABLE 7-3
The mean selling price of new homes in a small town over a year was $115,000.The population standard deviation was $25,000.A random sample of 100 new home sales from this city was taken.
-Referring to Table 7-3,without doing the calculations,state in which of the following ranges the sample mean selling price is most likely to lie?

Accepted Answer

A) $113,000 - $115,000 
B) $114,000 - $116,000 
C) $115,000 - $117,000 
D) $116,000 - $118,000

Question 19

TABLE 7-1
The manager of the customer service division of a major consumer electronics company is interested in determining whether the customers who have purchased a DVD player made by the company over the past 12 months are satisfied with their products.
-Referring to Table 7-1,the manager decides to ask a sample of customers,who have bought a DVD player made by the company and filed a complaint over the past year,to fill in a survey about whether they are satisfied with the product.This method will most likely suffer from

Accepted Answer

A) nonresponse error. 
B) measurement error. 
C) coverage error. 
D) nonprobability sampling.

Question 20

The amount of time it takes to complete an examination has a left skewed distribution with a mean of 65 minutes and a standard deviation of 8 minutes.If 64 students were randomly sampled,the probability that the sample mean of the sampled students exceeds 71 minutes is approximately 0.

Accepted Answer

A) True 
 B)False

Exam 7: Sampling and Sampling Distributions

A sample of size 25 provides a sample variance of 400.The standard error,in this case equal to 4,is best described as the estimate of the standard deviation of means calculated from samples of size 25.

The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed,with mean of 3.2 pounds and standard deviation of 0.8 pound.What percentage of samples of 4 fish will have sample means between 3.0 and 4.0 pounds?

The sample mean is an unbiased estimate of the population mean.

Assume that house prices in a neighborhood are normally distributed with a standard deviation of $20,000.A random sample of 16 observations is taken.What is the probability that the sample mean differs from the population mean by more than $5,000?

When dealing with human surveys,we are usually interested in sampling with replacement.

The Central Limit Theorem is important in statistics because

If the amount of gasoline purchased per car at a large service station has a population mean of 15 gallons and a population standard deviation of 4 gallons,then 99.73% of all cars will purchase between 3 and 27 gallons.

Coverage error results in a ________.

To find out the potential impact of a new zoning law on a neighborhood,the legislators conduct a focus group interview by inviting the members of the housing owners association of that neighborhood.This is an example of a

Items or individuals in a judgment sample are chosen according to their probability of occurrence.

________ results from the exclusion of certain groups of subjects from a population frame.

If the population distribution is symmetric,the sampling distribution of the mean can be approximated by the normal distribution if the samples contain 15 observations.

Which of the following yields a simple random sample?

The only way one can eliminate sampling error is to take the whole population as the sample.

The amount of time it takes to complete an examination has a left skewed distribution with a mean of 65 minutes and a standard deviation of 8 minutes.If 64 students were randomly sampled,the probability that the sample mean of the sampled students exceeds 71 minutes is approximately 0.