1.3 EXERCISES 24 CHAPTER 1 Introduction to Statistics For Extra Help: MyLab Statistics Building Basic Skills and Vocabulary 1. What is the difference between an observational study and an experiment? 2. What is the difference between a census and a sampling? 3. What is the difference between a random sample and a simple random sample? 4. What is replication in an experiment? Why is replication important? True or False? In Exercises 5–10, determine whether the statement is true or false. If it is false, rewrite it as a true statement. 5. A placebo is an actual treatment. 6. A double-blind experiment is used to increase the placebo effect. 7. Using a systematic sample guarantees that members of each group within a population will be sampled. 8. A convenience sample is always representative of a population. 9. The method for selecting a stratified sample is to order a population in some way and then select members of the population at regular intervals. 10. To select a cluster sample, divide a population into groups and then select all of the members in at least one (but not all) of the groups. Distinguishing Between an Observational Study and an Experiment In Exercises 11–14, determine whether the study is an observational study or an experiment. Explain. 11. A research study compared the memory retention of subjects when a learning activity was followed by a brief period of wakeful rest and when a learning activity was followed by a brief period of distraction. (Source: Springer Nature) 12. In a survey of U.S. employees, 42% of black women say they are uncomfortable sharing thoughts about racial inequality. (Source: McKinsey & Company) 13. A study used periodic blood pressure readings and brain MRIs of adults to find that adults with long periods of high blood pressure were more likely to develop cerebral small blood vessel disease. (Source: American Heart Association) 14. To study the effects of music on body image, researchers played a song with a body-positive message or a song with a body-negative message to different groups of women. (Source: Psychology of Popular Media) 15. Random Number Table Use the sixth row of Table 1 in Appendix B to generate 12 random numbers between 1 and 99. 16. Random Number Table Use the tenth row of Table 1 in Appendix B to generate 10 random numbers between 1 and 920. Random Numbers In Exercises 17 and 18, use technology to generate the random numbers. 17. Fifteen numbers between 1 and 150 18. Nineteen numbers between 1 and 1000
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