Question 1

Which of the following meets the requirements of a stratified random sample?

Accepted Answer

A)  A population contains 10 members under the age of 25 and 20 members over the age of 25.The sample will include six people who volunteer for the sample. 
B)  A population contains 10 members under the age of 25 and 20 members over the age of 25.The sample will include six people chosen at random,without regard to age. 
C)  A population contains 10 members under the age of 25 and 20 members over the age of 25.The sample will include six males chosen at random,without regard to age. 
D)  A population contains 10 members under the age of 25 and 20 members over the age of 25.The sample will include two people chosen at random under the age of 25 and four people chosen at random over 25. 
A)  A population contains 10 members under the age of 25 and 20 members over the age of 25.The sample will include six people who volunteer for the sample. 
B)  A population contains 10 members under the age of 25 and 20 members over the age of 25.The sample will include six people chosen at random,without regard to age. 
C)  A population contains 10 members under the age of 25 and 20 members over the age of 25.The sample will include six males chosen at random,without regard to age. 
D)  A population contains 10 members under the age of 25 and 20 members over the age of 25.The sample will include two people chosen at random under the age of 25 and four people chosen at random over 25.

Question 2

The office of career services at a major university knows that 74% of its graduates find full-time positions in the field of their choosing within six months of graduation.Suppose the office of career services surveys 25 alumni six months after graduation.a.What is the probability that at least 80% of the alumni have a job in the field of their choosing? b.What is the probability that between 60% and 76% of the alumni have a job in the field of their choosing? c.What is the probability that fewer than 60% of the alumni have a job in the field of their choosing?

Accepted Answer

If @#IMG-DLM& is normal,we can transform it into a

Question 3

A point estimator refers to an estimator that provides a single value.

Accepted Answer

A) True 
 B)False

Question 4

A random sample of 49 cast aluminum pots is taken from a production line once every day.The number of defective pots is counted.The proportion of defective pots has been closely examined in the past and is believed to be 0.05.The sample proportions for the week are shown in the accompanying table.   Is the production process in control?

Accepted Answer

A)  No,because the sample proportions show a downward trend. 
B)  No,because the sample proportions fall within the upper and lower control limits. 
C)  Yes,because the sample proportions show a downward trend. 
D)  Yes,because the sample proportions fall within the upper and lower control limits. 
A)  No,because the sample proportions show a downward trend. 
B)  No,because the sample proportions fall within the upper and lower control limits. 
C)  Yes,because the sample proportions show a downward trend. 
D)  Yes,because the sample proportions fall within the upper and lower control limits.

Question 5

It is known that college students at a local community college study 12 hours per week with a standard deviation of five hours.What are the expected value and variance for a sample of nine students?

Accepted Answer

The expected value of @#IMG-DLM& is the

Question 6

A ski resort gets an average of 2,000 customers per weekday with a standard deviation of 800 customers.Assume the underlying distribution is normal.What is the probability a ski resort averages between 1,500 customers and 3,000 customers per weekday over the course of four weekdays?

Accepted Answer

If @#IMG-DLM& is normal,we can transform it into a

Question 7

For any sample size n,the sampling distribution of   is normal if the population from which the sample is drawn is uniformly distributed.

Accepted Answer

A) True 
 B)False

Question 8

A school is required by the government to give some randomly chosen students a standardized test.From previous experience,the school knows about 68% of their students will receive passing scores in math and English.To improve funding,the school needs to score at least 70% on the standardized test.This year the school can decide if it wants to test 100 or 200 students.Should the school test 100 or 200 students? Explain the answer.

Accepted Answer

If @#IMG-DLM& is normal,we can transform it into a

Question 9

What is the relationship between the expected value of the sample mean and the expected value of the population?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 10

A local company makes snack-size bags of potato chips.Each day,the company produces batches of 400 snack-size bags using a process designed to fill each bag with an average of 2 ounces of potato chips.However,due to imperfect technology,the actual amount placed in a given bag varies.Assume the amount placed in each of the 400 bags is normally distributed and has a standard deviation of 0.1 ounce.What is the probability that a sample of 40 bags has an average weight of at least 2.02 ounces?

Accepted Answer

A)  0.0150 
B)  0.0918 
C)  0.1038 
D)  0.4207 
A)  0.0150 
B)  0.0918 
C)  0.1038 
D)  0.4207

Question 11

Nonresponse bias occurs when _______.

Accepted Answer

A)  the population has been divided into strata 
B)  portions of the population are excluded from the sample 
C)  cluster sampling is used instead of stratified random sampling 
D)  those responding to a survey or poll differ systematically from the nonrespondents 
A)  the population has been divided into strata 
B)  portions of the population are excluded from the sample 
C)  cluster sampling is used instead of stratified random sampling 
D)  those responding to a survey or poll differ systematically from the nonrespondents

Question 12

The California Department of Education wants to gauge the difficulty of a new exam by having a sample of students at a particular school take the exam.The quality of the students at the chosen school varies widely and the school administrators are allowed to choose who gets to take the exam.The administrators have a strong incentive for the school to do well on the exam.Do you think the results will represent the true ability of the students at school? What kind of bias,if any,do you think will be present? Explain.

Accepted Answer

The administrators will probably systema

Question 13

Over the entire six years that students attend an Ohio elementary school,they are absent,on average,28 days due to influenza.Assume that the standard deviation over this time period is σ = 9 days.Upon graduation from elementary school,a random sample of 36 students is taken and asked how many days of school they missed due to influenza.What is the expected value for the sampling distribution of the number of school days missed due to influenza?

Accepted Answer

A)  6 
B)  9 
C)  28 
D)  168 
A)  6 
B)  9 
C)  28 
D)  168

Question 14

Suppose that,on average,electricians earn approximately µ = $54,000 per year in the United States.Assume that the distribution for electricians' yearly earnings is normally distributed and that the standard deviation is σ = $12,000.Given a sample of four electricians,what is the standard deviation for the sampling distribution of the sample mean?

Accepted Answer

A)  6,000 
B)  12,000 
C)  36,000 
D)  54,000 
A)  6,000 
B)  12,000 
C)  36,000 
D)  54,000

Question 15

Over the entire six years that students attend an Ohio elementary school,they are absent,on average,28 days due to influenza.Assume that the standard deviation over this time period is σ = 9 days.Upon graduation from elementary school,a random sample of 36 students is taken and asked how many days of school they missed due to influenza.The probability that the sample mean is less than 30 school days is _______.

Accepted Answer

A)  0.0918 
B)  0.4129 
C)  0.5871 
D)  0.9082 
A)  0.0918 
B)  0.4129 
C)  0.5871 
D)  0.9082

Question 16

For making statistical inferences,it is essential that the sampling distribution of   is _________ distributed.

Accepted Answer

The answer of For making statistical inferences,it is essential that...

Question 17

How does the variance of the sample mean compare to the variance of the population?

Accepted Answer

A)  It is smaller and therefore suggests that averages have less variation than individual observations. 
B)  It is larger and therefore suggests that averages have less variation than individual observations. 
C)  It is smaller and therefore suggests that averages have more variation than individual observations. 
D)  It is larger and therefore suggests that averages have more variation than individual observations. 
A)  It is smaller and therefore suggests that averages have less variation than individual observations. 
B)  It is larger and therefore suggests that averages have less variation than individual observations. 
C)  It is smaller and therefore suggests that averages have more variation than individual observations. 
D)  It is larger and therefore suggests that averages have more variation than individual observations.

Question 18

According to the central limit theorem,the sampling distribution of   approached the normal distribution as the sample size _______.

Accepted Answer

The answer of According to the central limit theorem,the sampling...

Question 19

Administrative assistants in a local university have been asked to prove their proficiency in the use of spreadsheet software by taking a proficiency test.Historically,the mean test score has been 74 with a standard deviation of 4.A random sample of size 40 is taken from the 100 administrative assistants and asked to complete the proficiency test.a.Calculate the expected value and the standard deviation (standard error)of the sample mean.b.What is the probability that the sample mean score is more than 75,the predetermined passing score?

Accepted Answer

a.The expected value of the sample mean

Question 20

John would like to conduct a survey in his neighborhood to get homeowners' opinions on the Delmarva proposal to switch to natural gas.Which of the following is an example of a stratified sample?

Accepted Answer

A)  John randomly chooses three streets and selects every third house on those streets. 
B)  John selects the first 25 homes that he passes as he walks into the entrance of the development. 
C)  John selects every third house on each street. 
D)  John selects an equal number of two-story,split-level,and ranch houses. 
A)  John randomly chooses three streets and selects every third house on those streets. 
B)  John selects the first 25 homes that he passes as he walks into the entrance of the development. 
C)  John selects every third house on each street. 
D)  John selects an equal number of two-story,split-level,and ranch houses.

Which of the following meets the requirements of a stratified random sample?

A point estimator refers to an estimator that provides a single value.

It is known that college students at a local community college study 12 hours per week with a standard deviation of five hours.What are the expected value and variance for a sample of nine students?

A ski resort gets an average of 2,000 customers per weekday with a standard deviation of 800 customers.Assume the underlying distribution is normal.What is the probability a ski resort averages between 1,500 customers and 3,000 customers per weekday over the course of four weekdays?

For any sample size n,the sampling distribution of is normal if the population from which the sample is drawn is uniformly distributed.

What is the relationship between the expected value of the sample mean and the expected value of the population?

Nonresponse bias occurs when _______.

For making statistical inferences,it is essential that the sampling distribution of is _________ distributed.

How does the variance of the sample mean compare to the variance of the population?

According to the central limit theorem,the sampling distribution of approached the normal distribution as the sample size _______.

John would like to conduct a survey in his neighborhood to get homeowners' opinions on the Delmarva proposal to switch to natural gas.Which of the following is an example of a stratified sample?

Statistics and Data

Tabular and Graphical Methods

Numerical Descriptive Measures

Basic Probability Concepts

Discrete Probability Distributions

Continuous Probability Distributions

Interval Estimation

Hypothesis Testing

Statistical Inference Concerning Two Populations

Statistical Inference Concerning Variance

Chi-Square Tests

Analysis of Variance

Regression Analysis

Inference With Regression Models

Regression Models for Nonlinear Relationships

Regression Models With Dummy Variables

Time Series and Forecasting

Returns, Index Numbers and Inflation

Nonparametric Tests

Filters

Exam 7: Sampling and Sampling Distributions

Which of the following meets the requirements of a stratified random sample?

A point estimator refers to an estimator that provides a single value.

It is known that college students at a local community college study 12 hours per week with a standard deviation of five hours.What are the expected value and variance for a sample of nine students?

A ski resort gets an average of 2,000 customers per weekday with a standard deviation of 800 customers.Assume the underlying distribution is normal.What is the probability a ski resort averages between 1,500 customers and 3,000 customers per weekday over the course of four weekdays?

For any sample size n,the sampling distribution of is normal if the population from which the sample is drawn is uniformly distributed.

What is the relationship between the expected value of the sample mean and the expected value of the population?

Nonresponse bias occurs when _______.

For making statistical inferences,it is essential that the sampling distribution of is _________ distributed.

How does the variance of the sample mean compare to the variance of the population?

According to the central limit theorem,the sampling distribution of approached the normal distribution as the sample size _______.

John would like to conduct a survey in his neighborhood to get homeowners' opinions on the Delmarva proposal to switch to natural gas.Which of the following is an example of a stratified sample?

Statistics and Data

Tabular and Graphical Methods

Numerical Descriptive Measures

Basic Probability Concepts

Discrete Probability Distributions

Continuous Probability Distributions

Interval Estimation

Hypothesis Testing

Statistical Inference Concerning Two Populations

Statistical Inference Concerning Variance

Chi-Square Tests

Analysis of Variance

Regression Analysis

Inference With Regression Models

Regression Models for Nonlinear Relationships

Regression Models With Dummy Variables

Time Series and Forecasting

Returns, Index Numbers and Inflation

Nonparametric Tests

Filters