Researchers investigated the possible beneficial effect on heart health of drinking black tea and whether adding milk to the tea reduces any possible benefit. Twenty-four volunteers were randomly assigned to one of three groups. Every day for a month, participants in group 1 drank two cups of hot black tea without milk, participants in group 2 drank two cups of hot black tea with milk, and participants in group 3 drank two cups of hot water but no tea. At the end of the month, the researchers measured the change in each of the participants’ heart health.

a. Did the researchers conduct an experiment or an observational study? Explain.
b. Why did the researchers include a group who drank hot water but no tea?
c. Is it reasonable to generalize the results of the study beyond the 24 participants? Explain why or why not.

Options:

a) Experiment, because they manipulated variables and measured the effect.

b) To provide a control group for comparison and isolate the effects of tea consumption.

c) Yes, because a controlled experiment was conducted and random assignment was used.

b) To increase the sample size and improve the accuracy of the study.

c) No, because the sample size is too small to draw broad conclusions.

c) No, because the study lacks a control group for comparison.

d) Yes, because the participants were randomly assigned and represent a diverse population.

a. The researchers conducted an experiment, not an observational study. This is because they purposefully manipulated variables (the tea and milk) and measured the effects of these changes on the participants' heart health.

b. The researchers included a group that drank hot water but no tea to serve as a control group. This allows the researchers to compare the effects of drinking tea (with and without milk) with a 'baseline' group that didn't consume tea at all. This helps to isolate the effects of tea consumption on heart health.

c. It's not reasonable to generalize the results of the study beyond the 24 participants because the sample size is too small to draw broad conclusions. While the experiment is well-controlled and uses random assignment, the sample size is not large enough to accurately encompass the wide variability among all people.

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aditigupte1 aditigupte1 · Answer 2 · 2024-02-08T08:40:37-05:00

Final answer:

The study conducted by the researchers is an experiment as they manipulated the variables. A control group was included to provide a comparison and isolate the effects of tea. However, the results cannot be generalized to a broader population given the small sample size.

Explanation:

a) This is an experiment. The researchers intentionally changed the variables (tea with milk, tea without milk, and hot water) to observe any changes in heart health. Because they manipulated the variables, it's a classic definition of an experiment.

b) The group who drank hot water served as the control group. This group is essential to discern whether the changes in heart health are indeed due to the consumption of black tea or not. With this group, the researchers can compare and isolate the effects of tea consumption.

c) It is not reasonable to generalize the results of the study to a wider population. While the researchers used random assignment and controls, the sample size of 24 participants is quite small. To make broad generalizations, the study would need to include more people to account for a larger variety of individual health differences and responses.

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