To determine: The correct option for the type of the given experiment or study.
Answer to Problem 9.19CYS
Answer:
The correct option is (a) an observational study.
Explanation of Solution
Explanation:
Given info:
A representative sample constituted 6,906 U.S. adults. The sample was collected over a period of 20 years. The study revealed a statistically significant difference between life satisfaction between parents and nonparents, where “parents reported higher levels of life satisfaction than nonparents”.
Reason for correct answer:
The method of data collection is an observational study. In the observational study the inferences drawn from a sample to a population. Observational study based on past data.
In the given information the random samples of 6906 adults showed that the parents reported higher levels of life satisfaction that the nonparents. Since no treatment are required and inference is drawn from the sample by simply observing the values, hence it is an observational study.
Thus, option is (a) an observational study is correct.
Reason for incorrect answers:
Option (b) a randomized comparative experiment.
The randomized comparative experiment is an experiment that uses both comparison of two or more treatments and random assignment of subject to treatment. Since in the given example no treatment is applied by the researchers, therefore the Option (b) a randomized comparative experiment is incorrect.
Option (c) a matched pairs experiment.
The matched pairs design is a common design that combines matching with randomization. The matched pairs design is used when there are two treatments or conditions. It is a special case of randomized block design. In this method the subjects that are matched with each other are chosen as a pair. Then one subject from the pairs is selected randomly to get the first treatment, and then other subject gets the other treatment. Since in the given example no treatment is applied by the researchers, therefore the Option (c) a matched pairs experiment is incorrect.
Thus, options (b) and (c) are incorrect.
Conclusion:
Thus, the correct option is (a) an observational study and the given example is a observational study.
Introduction:
Observational Study:
An observational study measures the values of a variable without influencing the values of response variables and explanatory variables. Thus, in observational study researchers can observe the behaviors of the individuals without influencing the outcome of that study.
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