Either an experiment or an observational study may be used to detect an association between a response variable and an explanatory variable.




1- Explain why confounding (lurking) variables are a problem in the following observational study. Your explanation should be specific for this study.

"A study was conducted to determine if studying Latin in high school had an impact on college success. The college GPAs of a group of randomly selected students who mastered Latin in high school were compared to the college GPAs of a group of randomly selected students who did not take Latin in high school. The GPAs of the students who mastered Latin were found to be significantly higher on average than the GPAs of the other group, so the researchers concluded that mastering Latin in high school resulted in higher grades in college."



2- In a recent study on veterinary practices, 25 cases of negligence were discovered at ten randomly selected large veterinary hospitals in the state, compared to 12 cases of negligence at ten randomly selected small veterinary clinics in the state. Explain what is wrong with the following statement that was made after these data were collected: “the data show that it is safer to carry your pet to a small clinic because they resulted in fewer cases of negligence."







    • 5 years ago
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