Exam 1: What Is 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:

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

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

The confidence level of a statistical inference measures:

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

How do confidence levels compare to significance levels?

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

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

A study is under way to determine the average height of all 63,000 adult walnut trees in a certain national forest.The heights of 950 randomly selected adult walnut trees are measured and analyzed.The sample in this study is:

​One source of data used in thisChapter is the GSS.What does this acronym mean?

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.

The significance level of a statistical inference measures:

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:

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.

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 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 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.

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.

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 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: