In Exercises 9–20, identify which of these types of sampling is used: random, systematic, convenience, stratified, or cluster.
Reported and Observed Results A Harris Interactive study involved 1013 adults who were interviewed about washing their hands in restrooms and another 6336 adults who were observed in public restrooms.

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 results appear to have statistical significance, and also determine whether the results appear to have practical significance.

Mendel’s Genetics Experiments One of Gregor Mendel’s famous hybridization experiments with peas yielded 580 offspring with 152 of those peas (or 26%) having yellow pods. According to Mendel’s theory, 25% of the offspring peas should have yellow pods.

In Exercises 37–44, answer the given questions, which are related to percentages.

Checking Job Applicants In a study conducted by the Society for Human Resource Management, 347 human resource professionals were surveyed. Of those surveyed, 73% said that their companies conduct criminal background checks on all job applicants.

a. What is the exact value that is 73% of the 347 survey subjects?

b. Could the result from part (a) be the actual number of survey subjects who said that their companies conduct criminal background checks on all job applicants? Why or why not?

Quantitative/Categorical Data Identify each of the following as quantitative data or categorical data

c. The colors of the M&M candies in Data Set 38 “Candies” in Appendix B

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?