Parameter and Statistic In a Citrix Security survey of 1001 adults in the United States, it was found that 69% of those surveyed believe that having their personal information stolen is inevitable. Identify the population and sample. Is the value of 69% a statistic or a parameter?

In Exercises 29–32, identify the level of measurement of the data as nominal, ordinal, interval, or ratio. Also, explain what is wrong with the given calculation.

Social Security Numbers As part of a project in a statistics class, students report the last four digits of their Social Security numbers, and the average (mean) of those digits is computed to be 4.7.

In Exercises 9–12, determine whether the sampling method appears to be sound or is flawed.

Clinical Trials Researchers at Yale University conduct a wide variety of clinical trials by using subjects who volunteer after reading advertisements soliciting paid volunteers.

In Exercises 13–20, determine whether the data are from a discrete or continuous data set.

Students Your statistics professor records the number of students who pass each of her courses.

In Exercises 13–20, determine whether the data are from a discrete or continuous data set.

Statistics Classes In each of her classes, a statistics professor records the number of students who earned a grade of A.

Computer Virus In an AOL survey of Internet users, this question was posted online: “Have you ever been hit by a computer virus?” Among the 170,063 responses, 63% answered “yes.” What term is used to describe this type of survey in which the people surveyed consist of those who chose to respond? What is wrong with this type of sampling method?

Sampling Method The patients were recruited among those at a Veterans Affairs hospital. What type of sampling best describes the way in which the subjects were chosen: simple random sample, systematic sample, convenience sample, stratified sample, cluster sample? Does the method of sampling appear to adversely affect the quality of the results?