The paper "From Dr. Kildare to Grey's Anatomy" describes several studies of how the way in which doctors are
portrayed on television might influence public perception of doctors. One study was described as follows.

Rebecca Chory, Ph.D., now an associate professor of communication at West Virginia University,
began studying the effect of such portrayals on patients' attitudes toward physicians. Using a
survey of 300 undergraduate students, she compared perceptions of physicians in 1992—the end
of the era when physicians were shown as all-knowing, wise father figures—with those in 1999,
when shows such as ER and Chicago Hope (1994–2000) were continuing the transformation to
showing the private side and lives of physicians, including vivid demonstrations of their
weaknesses and insecurities.

Dr. Chory found that, regardless of the respondents' personal experience with physicians, those
who watched certain kinds of television had declining perceptions of physicians' composure and
regard for others. Her results indicated that the more prime time physician shows that people
watched in which physicians were the main characters, the more uncaring, cold, and unfriendly
the respondents thought physicians were.

(a) Answer the following four questions for the observational study described in this exercise. (Hint: Reviewing
Examples 1.4 and 1.5 might be helpful.)

(i) What is the population of interest?
patients that saw doctors after 1999
patients that saw doctors before 1992
all patients
TV doctors
real life doctors

(ii) Was the sample selected in a reasonable way?
Yes, the report explains the randomization scheme.
No, the sample size is too small.
Yes, the sample is large enough to be reasonable.
Yes, the sample included undergraduate students.
No, the report indicates no randomization

(iii) Is the sample likely to be representative of the population of interest?
Yes, undergraduate students were surveyed and they are representative of all patients.
Yes, 300 students is a large enough sample to represent the whole population.
No, the population of interest is TV doctors but only undergraduate students were surveyed.
No, the population of interest is real life doctors but only undergraduate students were surveyed.
No, the population of interest is all patients but only undergraduate students were surveyed

(iv) Are there any obvious sources of bias?
Selection bias, because only undergraduate students were chosen.
Nonresponse bias, because not all participants returned surveys.
There was bias against patients born after 1992 in the experimental design.
Measurement bias is present, because the survey used leading questions.
No sampling bias is present.

(b) Based on the study design, do you think that the stated conclusions are reasonable?
No, the stated conclusions are not reasonable because survey results cannot be generalized.
No, the stated conclusions are not reasonable because there was no random selection of study
participants, and the study suffers from selection bias.
No, the stated conclusions are not reasonable because there was measurement and nonresponse
bias in the study.
Yes, the stated conclusions are reasonable and can be generalized to all patients.