Exam 1: What Is Statistics

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

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

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 ____________________.

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?

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

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:

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

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

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

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

A researcher at Florida International University (FIU) wants to estimate the average number of credits earned by students last semester at FIU.She randomly selects 750 students from last semester and finds that they averaged 13.75 credits per student.The population of interest to the researcher is:

The confidence level of a statistical inference measures:

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 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 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) ____________________.

How do confidence levels compare to significance levels?

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:

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 descriptive measure of a sample is called a parameter.

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: