Question 1

For a sampling distribution of the means, what percent of the means would be between $\pm$ 1.96 standard deviations? ________________________

Accepted Answer

The answer of For a sampling distribution of the means,...

Question 2

A population consists of 12 values. How many samples of size six are possible?

Accepted Answer

The answer of A population consists of 12 values. How...

Question 3

When all the items in a population have an equal chance of being selected for a sample, the process is called _________________.

Accepted Answer

A)  Simple random sampling 
B)  z-score 
C)  Sampling error 
D)  Nonprobability sampling 
A)  Simple random sampling 
B)  z-score 
C)  Sampling error 
D)  Nonprobability sampling

Question 4

According to the central limit theorem,

Accepted Answer

A)  The population mean and the mean of all sample means are equal. 
B)  Increasing sample size decreases the dispersion of the sampling distribution. 
C)  The sampling distribution of the sample means is approximately normally distributed. 
D)  The sampling distribution of the sample means will be skewed. 
A)  The population mean and the mean of all sample means are equal. 
B)  Increasing sample size decreases the dispersion of the sampling distribution. 
C)  The sampling distribution of the sample means is approximately normally distributed. 
D)  The sampling distribution of the sample means will be skewed.

Question 5

Truck tire life is normally distributed with a mean of 60,000 miles and a standard deviation of 4,000 miles. What is the probability that a tire lasts between 54,000 and 66,000 miles?

Accepted Answer

A)  0.4332 
B)  0.8664 
C)  1.00 
D)  Very likely 
A)  0.4332 
B)  0.8664 
C)  1.00 
D)  Very likely

Question 6

A university has 1000 computers available for students to use. Each computer has a 250 gigabyte hard drive. The university wants to estimate the space occupied on the hard drives. A random sample of 100 computers showed a mean of 115 gigabytes used with a standard deviation of 20 gigabytes. What is the probability that a sample mean is greater than 200 gigabytes?

Accepted Answer

The answer of A university has 1000 computers available for...

Question 7

The mean of all the sample means is

Accepted Answer

A)    
B)  µ 
C)  $\sigma$ 
D)  a 
A)    
B)  µ 
C)  $\sigma$ 
D)  a

Question 8

What is the difference between a sample mean and the population mean called?

Accepted Answer

A)  Standard error of the mean 
B)  Sampling error 
C)  Interval estimate 
D)  Point estimate 
A)  Standard error of the mean 
B)  Sampling error 
C)  Interval estimate 
D)  Point estimate

Question 9

Truck tire life is normally distributed with a mean of 60,000 miles and a standard deviation of 4,000 miles. What is the probability that a tire will last 72,000 miles or more?

Accepted Answer

A)  0.0013 
B)  0.9987 
C)  0.4987 
D)  0.9544 
A)  0.0013 
B)  0.9987 
C)  0.4987 
D)  0.9544

Question 10

A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spend studying per week. Based on a simple random sample, they surveyed 144 students. The statistics showed that students studied an average of 20 hours per week with a standard deviation of 10 hours. What is the probability that a sample mean would exceed 20 hours per week?

Accepted Answer

A)  1.0 
B)  0.5 
C)  1.96 
D)  Cannot be calculated based on the given information. 
A)  1.0 
B)  0.5 
C)  1.96 
D)  Cannot be calculated based on the given information.

Question 11

When doing research, knowing the population mean, and other population parameters is essential.

Accepted Answer

A) True 
 B)False

Question 12

The size of the sampling error is

Accepted Answer

A)  Directly related to the sample size, i.e., the larger the sample size, the larger the sampling error. 
B)  Directly related to the population mean, i.e., the larger the mean, the larger the sampling error. 
C)  Inversely related to the sample size, i.e., the larger the sample size, the smaller the sampling error. 
D)  Inversely related to the population standard deviation, i.e., the smaller the standard deviation, the larger the sampling error. 
A)  Directly related to the sample size, i.e., the larger the sample size, the larger the sampling error. 
B)  Directly related to the population mean, i.e., the larger the mean, the larger the sampling error. 
C)  Inversely related to the sample size, i.e., the larger the sample size, the smaller the sampling error. 
D)  Inversely related to the population standard deviation, i.e., the smaller the standard deviation, the larger the sampling error.

Question 13

The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. Given a class with 9 students, what is the probability that the class' average IQ score is between 85 and 115?

Accepted Answer

A)  0.4987 
B)  3.00 
C)  0.0026 
D)  0.9974 
A)  0.4987 
B)  3.00 
C)  0.0026 
D)  0.9974

Question 14

A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spend studying per week. Based on a simple random sample, they surveyed 144 students. The statistics showed that students studied an average of 20 hours per week with a standard deviation of 10 hours. What is the standard error of the mean?

Accepted Answer

A)  0.83 
B)  10 
C)  0.5 
D)  2 
A)  0.83 
B)  10 
C)  0.5 
D)  2

Question 15

Mileage tests were conducted on a randomly selected sample of 100 newly developed automobile tires. The average tread wear was found to be 50,000 miles with a standard deviation of 3,500 miles. What is the best estimate of the average tread life in miles for the entire population of these tires?

Accepted Answer

A)  50,000 
B)  3,500 
C)  (50,000/100) 
D)  (3,500/100) 
A)  50,000 
B)  3,500 
C)  (50,000/100) 
D)  (3,500/100)

Question 16

A population consists of the following five values: 3, 8, 11, 13, and 16. From this population, there are 10 different samples of size 3. The means of the 10 samples of size 3 are: 7.33, 8, 9, 9, 10, 10.67, 10.67, 11.67, 12.33, 13.33. Compare the dispersion in the population with that of the sample means.

Accepted Answer

The standard deviation of the

Question 17

An accounting firm is planning for the next tax preparation season. From last year's returns, the firm collects a systematic random sample of 100 filings. The 100 filings showed an average preparation time of 90 minutes with a standard deviation of 140 minutes. What assumptions do you need to make about the shape of the population distribution of all possible tax preparation times to make inferences about the average time to complete a tax form?

Accepted Answer

A)  The population distribution is skewed to the right. 
B)  The population distribution is skewed to the left. 
C)  The population distribution is normal. 
D)  The shape of the population distribution does not matter. 
A)  The population distribution is skewed to the right. 
B)  The population distribution is skewed to the left. 
C)  The population distribution is normal. 
D)  The shape of the population distribution does not matter.

Question 18

When deciding to take a sample from a population, the amount of time required to take the sample is not important.

Accepted Answer

A) True 
 B)False

Question 19

The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability that a person would score 130 or more on the test?

Accepted Answer

A)  0.0228 
B)  0.9772 
C)  0.4772 
D)  0.9544 
A)  0.0228 
B)  0.9772 
C)  0.4772 
D)  0.9544

Question 20

Suppose we select every fifth invoice in a file. What type of sampling is this?

Accepted Answer

A)  Random 
B)  Cluster 
C)  Stratified 
D)  Systematic 
A)  Random 
B)  Cluster 
C)  Stratified 
D)  Systematic

For a sampling distribution of the means, what percent of the means would be between $\pm$ 1.96 standard deviations? ________________________

A population consists of 12 values. How many samples of size six are possible?

When all the items in a population have an equal chance of being selected for a sample, the process is called _________________.

According to the central limit theorem,

Truck tire life is normally distributed with a mean of 60,000 miles and a standard deviation of 4,000 miles. What is the probability that a tire lasts between 54,000 and 66,000 miles?

The mean of all the sample means is

What is the difference between a sample mean and the population mean called?

Truck tire life is normally distributed with a mean of 60,000 miles and a standard deviation of 4,000 miles. What is the probability that a tire will last 72,000 miles or more?

When doing research, knowing the population mean, and other population parameters is essential.

The size of the sampling error is

The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. Given a class with 9 students, what is the probability that the class' average IQ score is between 85 and 115?

Mileage tests were conducted on a randomly selected sample of 100 newly developed automobile tires. The average tread wear was found to be 50,000 miles with a standard deviation of 3,500 miles. What is the best estimate of the average tread life in miles for the entire population of these tires?

When deciding to take a sample from a population, the amount of time required to take the sample is not important.

The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability that a person would score 130 or more on the test?

Suppose we select every fifth invoice in a file. What type of sampling is this?

What Is Statistics

Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation

Describing Data: Numerical Measures

Describing Data: Displaying and Exploring Data

A Survey of Probability Concepts

Discrete Probability Distributions

Continuous Probability Distributions

Estimation and Confidence Intervals

One-Sample Tests of Hypothesis

Two-Sample Tests of Hypothesis

Analysis of Variance

Correlation and Linear Regression

Multiple Regression Analysis

Index Numbers

Time Series and Forecasting

Nonparametric Methods: Goodness-Of-Fit Tests

Nonparametric Methods: Analysis of Ranked Data

Statistical Process Control and Quality Management

An Introduction to Decision Theory

Filters

Exam 8: Sampling Methods and the Central Limit Theorem

For a sampling distribution of the means, what percent of the means would be between ±\pm± 1.96 standard deviations? ________________________

A population consists of 12 values. How many samples of size six are possible?

When all the items in a population have an equal chance of being selected for a sample, the process is called _________________.

According to the central limit theorem,

Truck tire life is normally distributed with a mean of 60,000 miles and a standard deviation of 4,000 miles. What is the probability that a tire lasts between 54,000 and 66,000 miles?

The mean of all the sample means is

What is the difference between a sample mean and the population mean called?

Truck tire life is normally distributed with a mean of 60,000 miles and a standard deviation of 4,000 miles. What is the probability that a tire will last 72,000 miles or more?

When doing research, knowing the population mean, and other population parameters is essential.

The size of the sampling error is

The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. Given a class with 9 students, what is the probability that the class' average IQ score is between 85 and 115?

Mileage tests were conducted on a randomly selected sample of 100 newly developed automobile tires. The average tread wear was found to be 50,000 miles with a standard deviation of 3,500 miles. What is the best estimate of the average tread life in miles for the entire population of these tires?

When deciding to take a sample from a population, the amount of time required to take the sample is not important.

The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability that a person would score 130 or more on the test?

Suppose we select every fifth invoice in a file. What type of sampling is this?

What Is Statistics

Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation

Describing Data: Numerical Measures

Describing Data: Displaying and Exploring Data

A Survey of Probability Concepts

Discrete Probability Distributions

Continuous Probability Distributions

Estimation and Confidence Intervals

One-Sample Tests of Hypothesis

Two-Sample Tests of Hypothesis

Analysis of Variance

Correlation and Linear Regression

Multiple Regression Analysis

Index Numbers

Time Series and Forecasting

Nonparametric Methods: Goodness-Of-Fit Tests

Nonparametric Methods: Analysis of Ranked Data

Statistical Process Control and Quality Management

An Introduction to Decision Theory

Filters

For a sampling distribution of the means, what percent of the means would be between $\pm$ 1.96 standard deviations? ________________________