Question 1

Instruction 7-2
The mean selling price of new homes in a country town over a year was $115,000.The population standard deviation was $25,000.A random sample of 100 new home sales from this town was taken.
-Referring to Instruction 7-2,what is the probability that the sample mean selling price was between $114,000 and $116,000?

Accepted Answer

The answer of Instruction 7-2
The mean selling price of new...

Question 2

Which of the following is NOT a reason for the need for sampling?

Accepted Answer

A) It is usually too costly to study the whole population. 
B) It is always more informative by investigating a sample than the entire population. 
C) It is sometimes destructive to observe the entire population. 
D) It is usually too time consuming to look at the whole population.

Question 3

Instruction 7-4
According to a survey,only 15% of customers who visited the web site of a major retail store made a purchase.Random samples of size 50 are selected.
-Referring to Instruction 7-4,what is the probability that a random sample of 50 will have at least 30% of customers who will make a purchase after visiting the web site?

Accepted Answer

The answer of Instruction 7-4
According to a survey,only 15% of...

Question 4

Instruction 7-6
According to an article,19% of the entire Australian population have high-speed access to the Internet.Random samples of size 200 are selected from the Australian population.
-Referring to Instruction 7-6,among all the random samples of size 200,90% will have more than ________% who have high-speed access to the Internet.

Accepted Answer

The answer of Instruction 7-6
According to an article,19% of the...

Question 5

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

Accepted Answer

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

Question 6

Instruction 7-6
According to an article,19% of the entire Australian population have high-speed access to the Internet.Random samples of size 200 are selected from the Australian population.
-Referring to Instruction 7-6,among all the random samples of size 200,________% will have less than 20% who have high-speed access to the Internet.

Accepted Answer

The answer of Instruction 7-6
According to an article,19% of the...

Question 7

As the size of the sample is increased,the standard deviation of the sampling distribution of the sample mean for a normally distributed population will stay the same.

Accepted Answer

A) True 
 B)False

Question 8

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

Accepted Answer

A) True 
 B)False

Question 9

Suppose a sample of n = 50 items is 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 probability distribution with μ = 180 grams and σ = 75 grams.Which of the following is true about the sampling distribution of the sample mean if a sample size of 15 is selected?

Accepted Answer

A) The shape of the sample distribution is approximately normal. 
B) The standard deviation of the sampling distribution is 75 grams. 
C) The mean of the sampling distribution is 180 grams. 
D) All of the above are correct.

Question 10

The amount of pyridoxine (in grams)per multiple vitamin is normally distributed with μ = 110 grams and σ = 25 grams.A sample of 25 vitamins is to be selected.What is the probability that the sample mean will be less than 100 grams?

Accepted Answer

The answer of The amount of pyridoxine (in grams)per multiple...

Question 11

The Central Limit Theorem ensures that the sampling distribution of the sample mean approaches normal as the sample size increases.

Accepted Answer

A) True 
 B)False

Question 12

If you randomly select a student from the first row of a business statistics class and then every other 5 students thereafter until you get a sample of 20 students,this is an example of a convenience sample.

Accepted Answer

A) True 
 B)False

Question 13

Suppose the ages of students in first-year Statistics 101 follow a skewed-right distribution with a mean of 23 years and a standard deviation of 3 years.If we randomly sampled 100 students,which of the following is true about the sampling distribution of the sample mean?

Accepted Answer

A) The shape of the sampling distribution is approximately normal. 
B) The mean of the sampling distribution is equal to 23 years. 
C) The standard deviation of the sampling distribution is equal to 3 years. 
D) The standard error of the sampling distribution is equal to 0.3 years.

Question 14

Which of the following is NOT a source of measurement error?

Accepted Answer

A) The halo effect. 
B) Respondent error. 
C) Ambiguous wording of questions. 
D) None of the above.

Question 15

When the results of non-probability samples are used to make conclusions about the entire population,ethical issues are also likely to arise.

Accepted Answer

A) True 
 B)False

Question 16

The question "How many times have you abused your spouse in the last 6 months?" will most likely result in non-response error.

Accepted Answer

A) True 
 B)False

Question 17

A statistic calculated from a sample is used to estimate the corresponding

Accepted Answer

A) sample. 
B) parameter. 
C) distribution. 
D) statistic.

Question 18

Australian football salaries averaged $150,000 with a standard deviation of $80,000 in a recent year.Suppose a sample of 100 football players was taken.Find the approximate probability that the average salary of the 100 players exceeded $100,000.

Accepted Answer

A) Approximately 1 
B) 0.2357 
C) 0.7357 
D) Approximately 0

Question 19

Assume that house prices in a neighbourhood are normally distributed with standard deviation $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 neighbourhood...

Question 20

To use the normal distribution to approximate the binomial distribution,we need ________ and ________ to be at least 5.

Accepted Answer

The answer of To use the normal distribution to approximate...

Exam 7: Sampling Distributions

Which of the following is NOT a reason for the need for sampling?

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

As the size of the sample is increased,the standard deviation of the sampling distribution of the sample mean for a normally distributed population will stay the same.

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

The amount of pyridoxine (in grams)per multiple vitamin is normally distributed with μ = 110 grams and σ = 25 grams.A sample of 25 vitamins is to be selected.What is the probability that the sample mean will be less than 100 grams?

The Central Limit Theorem ensures that the sampling distribution of the sample mean approaches normal as the sample size increases.

If you randomly select a student from the first row of a business statistics class and then every other 5 students thereafter until you get a sample of 20 students,this is an example of a convenience sample.

Suppose the ages of students in first-year Statistics 101 follow a skewed-right distribution with a mean of 23 years and a standard deviation of 3 years.If we randomly sampled 100 students,which of the following is true about the sampling distribution of the sample mean?

Which of the following is NOT a source of measurement error?

When the results of non-probability samples are used to make conclusions about the entire population,ethical issues are also likely to arise.

The question "How many times have you abused your spouse in the last 6 months?" will most likely result in non-response error.

A statistic calculated from a sample is used to estimate the corresponding

Australian football salaries averaged $150,000 with a standard deviation of $80,000 in a recent year.Suppose a sample of 100 football players was taken.Find the approximate probability that the average salary of the 100 players exceeded $100,000.

Assume that house prices in a neighbourhood are normally distributed with standard deviation $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?

To use the normal distribution to approximate the binomial distribution,we need and to be at least 5.