Question 1

The significance level measures the proportion of the time an inference about a population will be correct in the long run.

Accepted Answer

The significance level, typically denoted by alpha (α), is the probability of rejecting the null hypothesis when it is actually true. It is not a measure of the proportion of correct inferences in the long run. This definition is more in line with the concept of the confidence level, which is the proportion of intervals that contain the true population parameter in the long run.

Question 2

A councilman who is running for the office of senator of a state with 3.5 million registered voters commissions a survey. In the survey, 46% of the 8,000 registered voters interviewed say they plan to vote for him. The population of interest is:
A)the 3.5 million registered voters in the state.
B)the 8,000 registered voters interviewed.
C)the 46% who plan to vote for her.
D)all the residents of the state.

Accepted Answer

The population of interest is the entire population of registered voters in the state, not just the 8,000 interviewed or the percentage of voters supporting the councilman. The councilman wants to know how many votes he can expect from the whole population, not just from the surveyed sample.

Question 3

A summary measure that is computed from a sample is called a statistic.

Accepted Answer

A statistic is a measure that represents a characteristic of a sample, and it is used to estimate or infer information about the population from which the sample was drawn. Examples of statistics include the sample mean, standard deviation, correlation coefficient, and proportion. In contrast, a parameter is a summary measure that describes a characteristic of the entire population.

Question 4

Which of the following is a measure of the reliability of a statistical inference?
A)A population parameter.
B)A significance level.
C)A descriptive statistic.
D)A sample statistic.

Accepted Answer

A significance level (often denoted as alpha or α) is a measure used in hypothesis testing to determine the threshold at which the null hypothesis is rejected, thus it directly relates to the reliability of a statistical inference. It essentially indicates how strong the evidence must be before we can conclude that an effect is statistically significant and not just due to random chance.

Question 5

A summary measure that is computed from a population is called a:
A)sample.
B)statistic.
C)population.
D)parameter.

Accepted Answer

A summary measure computed from a population is referred to as a parameter.

Question 6

A descriptive measure of a sample is called a parameter.

Accepted Answer

A descriptive measure of a sample is called a statistic, whereas a parameter refers to a descriptive measure of a population.

Question 7

You take a random sample to estimate a population mean and your results have a confidence level of 80%. That means the process you used will give you correct results 80% of the time.

Accepted Answer

The answer of You take a random sample to estimate...

Question 8

A descriptive measure of a population is called a parameter.

Accepted Answer

This is correct. A parameter is a descriptive measure that describes a characteristic or feature of a population, such as the mean or variance.

Question 9

A resort employs 3,500 managers and staff. To ascertain their employees' opinions of a proposed health insurance plan, 350 employees are surveyed at random. The proportion of the 350 employees who favor the health insurance plan represents a parameter in this scenario.

Accepted Answer

The proportion of the 350 employees who favor the health insurance plan represents a statistic, not a parameter, because it is a measure derived from a sample of the population, not the entire population itself.

Question 10

A population is the group of all items of interest to a statistics practitioner.

Accepted Answer

A population includes all individuals or items of interest in a study or analysis.

Question 11

A statistic is typically a known quantity while a parameter is typically an unknown quantity.

Accepted Answer

This is a basic definition in statistics.

Question 12

In a sample of 350 students selected from a large college of business, 25% are found to be marketing majors. The 25% is a statistic.

Accepted Answer

The statement refers to a proportion of a sample, which is a statistic.

Question 13

A random sample of 100 students is taken at LearnAll University and it's found that their average GPA is 3.1. If this information is used to help estimate the average GPA for all students at LearnAll University, which branch of statistics was applied?
A)Descriptive statistics
B)Inferential statistics
C)Sample statistics
D)Population statistics

Accepted Answer

Inferential statistics was applied because the sample average GPA was used to make an estimate about the average GPA for all students at the university, which is a population parameter.

Question 14

A company has developed a new power cell and wants to estimate its average lifetime. A random sample of 650 power cells is tested and the average lifetime of this sample is found to be 315 hours. The 315 hours is the value of a:
A)parameter.
B)statistic.
C)sample.
D)population.

Accepted Answer

The 315 hours represents the average lifetime of the sample, so it is a statistic. A parameter is a numerical value that describes a characteristic of a population, which is not known in this case. Sample refers to the group of 650 power cells that were tested, and population refers to all possible power cells of this type, which is not known in this case either.

Question 15

The process of using sample statistics to draw conclusions about population parameters is called:
A)finding the significance level.
B)calculating descriptive statistics.
C)doing inferential statistics.
D)calculating the confidence level.

Accepted Answer

Inferential statistics is the process of using sample statistics to make inferences about population parameters. It involves hypothesis testing, estimation, and prediction. The other options are not accurate descriptions of this process.

Question 16

The confidence level is the proportion of times that an estimating procedure will be wrong in the long run.

Accepted Answer

The confidence level is the proportion of times that an estimating procedure will be correct in the long run.

Question 17

A company has developed a new engine whose average lifetime is unknown. In order to estimate this average, 100 engines are randomly selected from a large production line and tested; their average lifetime is found to be 11 years. The 11 years represents a:
A)parameter.
B)statistic.
C)sample.
D)population.

Accepted Answer

The 11 years represents the average lifetime of the 100 engines that were randomly selected and tested, which is a statistic. It is not a parameter because it is not a fixed value that represents the true average lifetime of all engines produced by the company. The sample refers to the 100 engines that were selected and tested, and the population refers to all engines produced by the company.

Question 18

A descriptive measure that is computed from a sample is called a:
A)parameter.
B)statistic.
C)population.
D)sample.

Accepted Answer

A statistic is a descriptive measure that is computed from a sample, while a parameter is a descriptive measure that is computed from a population. The population and sample refer to the entire group and the subset chosen from the group, respectively.

Question 19

A company has developed a new computer microprocessor whose average lifetime is unknown. In order to estimate this average, 300 microprocessors are randomly selected from a large production line and tested; their average lifetime is found to be 7 years. The 300 microprocessors represent a:
A)parameter.
B)statistic.
C)sample.
D)population.

Accepted Answer

The 300 microprocessors represent a sample, as they are a subset of the larger population of microprocessors produced by the company.

Question 20

Statistical inference is the process of making an estimate, prediction, or decision about a population based on sample data.

Accepted Answer

The statement accurately describes the concept of statistical inference.

Quiz 1: What Is Statistics

The significance level measures the proportion of the time an inference about a population will be correct in the long run.

A councilman who is running for the office of senator of a state with 3.5 million registered voters commissions a survey. In the survey, 46% of the 8,000 registered voters interviewed say they plan to vote for him. The population of interest is:

A summary measure that is computed from a sample is called a statistic.

Which of the following is a measure of the reliability of a statistical inference?

A summary measure that is computed from a population is called a:

A descriptive measure of a sample is called a parameter.

You take a random sample to estimate a population mean and your results have a confidence level of 80%. That means the process you used will give you correct results 80% of the time.

A descriptive measure of a population is called a parameter.

A resort employs 3,500 managers and staff. To ascertain their employees' opinions of a proposed health insurance plan, 350 employees are surveyed at random. The proportion of the 350 employees who favor the health insurance plan represents a parameter in this scenario.

A population is the group of all items of interest to a statistics practitioner.

A statistic is typically a known quantity while a parameter is typically an unknown quantity.

In a sample of 350 students selected from a large college of business, 25% are found to be marketing majors. The 25% is a statistic.

A random sample of 100 students is taken at LearnAll University and it's found that their average GPA is 3.1. If this information is used to help estimate the average GPA for all students at LearnAll University, which branch of statistics was applied?

A company has developed a new power cell and wants to estimate its average lifetime. A random sample of 650 power cells is tested and the average lifetime of this sample is found to be 315 hours. The 315 hours is the value of a:

The process of using sample statistics to draw conclusions about population parameters is called:

The confidence level is the proportion of times that an estimating procedure will be wrong in the long run.

A company has developed a new engine whose average lifetime is unknown. In order to estimate this average, 100 engines are randomly selected from a large production line and tested; their average lifetime is found to be 11 years. The 11 years represents a:

A descriptive measure that is computed from a sample is called a:

A company has developed a new computer microprocessor whose average lifetime is unknown. In order to estimate this average, 300 microprocessors are randomly selected from a large production line and tested; their average lifetime is found to be 7 years. The 300 microprocessors represent a:

Statistical inference is the process of making an estimate, prediction, or decision about a population based on sample data.