For Exercises 3.42 to 3.44, see pages 144–145; for 3.45, see page 146; for 3.46 and 3.47, see page 147; for 3.48 and 3.49, see page 150; for 3.50 and 3.51, see page 152; for 3.52, see page 153; for 3.53 and 3.54, see page 154; and for 3.55, see page 156.
3.45 Does using statistical software improve exam scores?
An instructor in an elementary statistics course wants to know if using a new statistical software package will improve students’ final-exam scores. He asks for volunteers, and approximately half of the class agrees to work with the new software. He compares the final-exam scores of the students who used the new software with the scores of those who did not. Discuss possible sources of bias in this study.
3.45
For those students who volunteered, they could have attributes that lead them to volunteer and also do better on the final. For example, they might be more willing to work hard or might enjoy studying, which may make them more willing to agree to use the new software and also do better on the final.