Question

Do ethnic group and gender influence the type of care that a heart patient receives? The following passage is from the article "Heart Care Reflects Race and Sex, Not Symptoms" (USA Today, February 25,1999\():\) Previous research suggested blacks and women were less likely than whites and men to get cardiac catheterization or coronary bypass surgery for chest pain or a heart attack. Scientists blamed differences in illness severity, insurance coverage, patient preference, and health care access. The researchers eliminated those differences by videotaping actors-two black men, two black women, two white men, and two white women - describing chest pain from identical scripts. They wore identical gowns, used identical gestures, and were taped from the same position. Researchers asked 720 primary care doctors at meetings of the American College of Physicians or the American Academy of Family Physicians to watch a tape and recommend care. The doctors thought the study focused on clinical decision making. Which video a particular doctor watched was determined by the roll of a four- sided die. Answer the following seven questions for the described experiment. (Hint: Reviewing Examples 1.5 and 1.6 might be helpful.) 1\. What question is the experiment trying to answer? 2\. What are the experimental conditions (treatments) for this experiment? 3\. What is the response variable? 4\. What are the experimental units, and how were they selected? 5\. Does the design incorporate random assignment of experimental units to the different experimental conditions? If not, are there potentially confounding variables that would make it difficult to draw conclusions based on data from the experiment? 6\. Does the experiment incorporate a control group and/or a placebo group? If not, would the experiment be improved by including them? 7\. Does the experiment involve blinding? If not, would the experiment be improved by making it single- or doubleblind?

Short answer

1. The experiment is trying to answer if ethnic group and gender influence the care recommendation for a heart patient. 2. The different actors' videos (under ethnic group and gender categories) that the doctors watched are the experimental conditions. 3. The care recommendation by the doctors is the response variable. 4. The doctors selected to watch videos by a roll of a die are the experimental units. 5. Yes, the experiment incorporated random assignment, which helps minimize confounding variables. 6. No, there was no control or placebo group, their presence could have helped measure the treatment effect. 7. Yes, the experiment involved single-blinding to avoid bias in doctors' decisions.

Step-by-step solution

Understanding the Experiment

The first step is to read the passage carefully to understand the topic, goals, and design of the experiment. The experiment is about seeing if ethnic group and gender influence the type of care that a heart patient receives. The experiment is conducted by having doctors watch videos of actors (of different ethnicities and genders) descriIt is also vital that you understand the setup in which doctors had to offer their care recommendations.

Questions 1 and 2: Experiment Goal and Conditions

The writer can now answer the first two questions. The experiment is trying to answer if ethnic group and gender influence the care recommendation given by doctors for a heart patient. The experimental conditions of this experiment are the different actors' videos (under the categories of ethnic group and gender) that the doctors watched.

Questions 3 and 4: Response Variable and Experimental Units

The response variable of this experiment is the care recommendation of the doctors after they watched a video clip. The experimental units here are the doctors themselves, who were selected to watch a particular video based on the roll of a die.

Questions 5: Random Assignment and Confounding Variables

There is random assignment of experimental units because which video a particular doctor watched was determined by the roll of a dice. If there was not random assignment of doctors it would be difficult to draw conclusions based on data from the experiment due to potentially confounding variables such as doctors' personal beliefs and experiences.

Questions 6: Control Group and Placebo Group

There is no direct mention of a control group or a placebo group in the experiment. Ideally, to improve the design of the experiment, they could have incorporated doctors watching a 'neutral' video as a control group. The presence of a control group could have helped measure the effect of the treatment (i.e., the influence of the actors' ethnicities and genders) by comparison.

Question 7: Blinding

The experiment involved single-blinding: the doctors thought the study was focused on clinical decision making, and were not aware of the gender and ethnicity variable being tested. Single-blinded experiments help avoid bias, as the doctors’ decisions were not influenced by knowing the objective of the experiment.