Exam 1: What Is Statistics

A descriptive measure of a sample is called a parameter.

The Attorney General of the state of California wanted to study criminal law in Los Angeles last year. He randomly selected 46,000 criminal records from the population of 1.5 million convicts in Los Angeles last year. From this sample, he calculated the proportion of litigations, the average amount of money involved per litigation, and the proportion of litigations resulting in a conviction. These calculations are all examples of doing ____________________ statistics.

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 confidence level of a statistical inference measures:

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:

Which of the following represents a population, as opposed to a sample?

A study is under way to determine the average height of all 29,000 adult pine trees in a certain national forest. The heights of 600 randomly selected adult pine trees are measured and analyzed. The parameter in the study is:

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:

How do confidence levels compare to significance levels?

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.

The Human Resources Director at Illinois State University wishes to develop an employee pension package. To get an idea of what components of a pension package are most important, he selects 525 employees at random and asks them for their opinions. The group of all employees at ISU is known as the ____________________.

The Human Resources Director of a large hospital wants to determine the percentage of all employees who favor a newly proposed benefits package. He selects 300 employees at random and finds that 85% approve the newly proposed package. The percentage of all employees of this company who favor the newly proposed package is a(n) ____________________.

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

The confidence level is the proportion of times that an estimating procedure will be wrong 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:

The Human Resources Director at Florida Atlantic University wishes to develop an employee benefits package. To get an idea of what components of a benefits package are most important, he selects 350 employees at random and asks them for their opinions. Numerically summarizing the preferences of these 350 employees is an example of doing ____________________ statistics.

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

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?

The Commissioner of Health in the state of New York wanted to study malpractice litigation in Albany last year. She randomly selected 53,000 medical records from the population of 2.5 million patients in Albany last year. The proportion of malpractice claims filed from the 53,000 patients is an example of a(n) ____________________.

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