Does regular exercise reduse the risk of a heart attack? Provided are two ways to study this question. 1. A researcher finds 2000 men older than age 40 who exercise regularly and have not had heart attacks. She matches each with a similar man who does not exercise regularly, and she follows both groups for 5 years. 2. Another researcher finds 4000 men older than age 40 who have not had heart attacks and are willing to participate in a study. She assigns 2000 of the men to a regular program of supervised exercise. The other 2000 continue their usual habits. The researcher follows both groups for 5 years, Select the correct explanation clearly detailing why the second design will produce more trustworthy data. 1) The first design is an observational study whereas the second design is an experiment. Assigning subjects to treatments, as in the second design, avoids confounding. 2) In the second design, the subjects are chosen in a random fashion, whereas in the first design the subjects from the second group are matched to the subjects in the first group. 3) The first design is an experiment whereas the second design is an observational study. Assigning subjects to treatments, as in the first design, does not avoid confounding. 4) In the first design, subjects are assigned to groups based on their own habits. There may be other factor (e.g., personality type or genetic background) that make one more likely to exercise and less (or more) likely to have a heart attack.

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Does regular exercise reduse the risk of a heart attack? Provided are two ways to study this question.  1. A researcher finds 2000 men older than age 40 who exercise regularly and have not had heart attacks. She matches each with a similar man who does not exercise regularly, and she follows both groups for 5 years.  2. Another researcher finds 4000 men older than age 40 who have not had heart attacks and are willing to participate in a study. She assigns 2000 of the men to a regular program of supervised exercise. The other 2000 continue their usual habits. The researcher follows both groups for 5 years,  Select the correct explanation clearly detailing why the second design will produce more trustworthy data.  1) The first design is an observational study whereas the second design is an experiment. Assigning subjects to treatments, as in the second design, avoids confounding.  2) In the second design, the subjects are chosen in a random fashion, whereas in the first design the subjects from the second group are matched to the subjects in the first group.  3) The first design is an experiment whereas the second design is an observational study. Assigning subjects to treatments, as in the first design, does not avoid confounding.  4) In the first design, subjects are assigned to groups based on their own habits. There may be other factor (e.g., personality type or genetic background) that make one more likely to exercise and less (or more) likely to have a heart attack.

gwibdaithq · Accepted Answer

Step 1  Observational study:  If the examiner monitors the behaviour of the individuals and provides the conclusions for the study, then the study is an observational study. In other words, the examiner only observes what is occurring or what has occurred in the past and gives inferences for the study.  Experimental study:  If the examiner influences or manipulates one of the variables in the study and verifies how it impacts other variables, then the study is an experimental study. In other words, the examiner manipulates one variable and determines how this variable influences the other variables.  Step 2  Here, the two designs are given as follows:  A researcher finds 2000 men older than age 40 who exercise regularly and have not had heart attacks. She matches each with a similar man who does not exercise regular and she follows both groups for 5 years.  2) Another researcher finds 4000 men older than 40 who have not had heart attacks and are willing to participate in a study. She assigns 2000 of the men to a regular program of supervised exercise. The other 2000 continue their usual habits. The researcher follows both group for 5 years.  Using the above definitions, we can observe that the first design is an observational study and second design is an experiment.  In first design, second group is selected as matched pair of first group it is not a random assignment.  In second design, researcher conducts experiment by assigning the subjects to two different groups. The one group of supervised exercise and other group of regular habits.  Step 3  Thus, the correct explanations are,  The first design is an observational study whereas the second design is an experiment. Assigning subjects to treatments as in second design avoids confounding.  In the second design, the subjects are chosen in a random fashion, whereas in the first design the subjects from the second group are matched to the subjects in the first group.  In the first design, subjects are assigned to groups based on their own habits. There may be other factors(eg, personality type or genetic background) that make one more likely to exercise and less (or more) to have a heart attack.

nick1337 · Accepted Answer

The correct explanation is:1) The first design is an observational study, whereas the second design is an experiment. Assigning subjects to treatments, as in the second design, avoids confounding.In the first design, the researcher observes a group of 2000 men who exercise regularly and matches each of them with a similar man who does not exercise regularly. This is an observational study because the researcher is merely observing and comparing two groups based on their exercise habits. However, there may be confounding factors that could influence the results. For example, the men who exercise regularly may have other healthy lifestyle habits or genetic factors that make them less likely to have a heart attack, independent of exercise.On the other hand, the second design is an experiment. The researcher selects 4000 men who have not had heart attacks and assigns 2000 of them to a regular program of supervised exercise, while the other 2000 continue their usual habits. By randomly assigning subjects to the treatment (exercise) and control (no exercise) groups, the researcher can minimize the influence of confounding factors. Randomization helps ensure that any differences observed between the two groups can be attributed to the treatment (regular exercise) rather than other variables.Therefore, the second design is more trustworthy in producing reliable data because it is an experimental design with random assignment, which helps reduce the impact of confounding factors and strengthens the causal inference between regular exercise and the risk of a heart attack.

Does regular exercise reduse the risk of a heart attack? Provided are two ways t

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