Exam 1: What Is Statistics

Briefly describe the difference between a parameter and a statistic, and give an example of each.

The Surgeon General wanted to study malpractice litigation in Chicago. A sample of 32,000 medical records was selected from all 3.5 million patients who were discharged during the year 2011. Using the information from the sample to make conclusions about malpractice litigation in Chicago is an example of doing ____________________ statistics.

The confidence level of a statistical inference measures:

A candidate who is running for the vacant City Mayor seat with 35,000 registered voters wants to determine what percentage would vote for him. His pollsters interview 600 registered voters from the city at random; 60% say they plan to vote for him. a.What is the population of interest? b.What is the sample? c.Is the 60% a parameter or a statistic in this scenario? Why?

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

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

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

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

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.

Each of the following is a form of doing ____________________ statistics: 1) presenting your data using a graph; 2) calculating the mean of your sample; and 3) organizing your data into a table.

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 Owner of a large manufacturing company wishes to develop a new employee health benefits package. He selects 500 employees at random and asks them about their preferences regarding their current health benefits package. The 500 employees selected is a(n) ____________________.

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

The significance level of a statistical inference measures:

How do confidence levels compare to significance levels?

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 descriptive measure of a sample is called a parameter.

At Cedar Rapids Community College, administrators want to determine the average commuting distance for their students who commute to school. They randomly select 250 students who commute and ask them the distance of their commute to campus. From this group a mean of 19.3 miles is computed. a.Describe/find the parameter. b.Describe/find the statistic. c.Describe the population. d.Describe the sample.

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