Question

(1 point) is there an association between the use of computerized system and hospital mortality? in a large - scale hospital study, the study investigator randomly sampled 35 hospitals from all hospitals in texas. within each of the sampled hospitals, 500 patients who were hospitalized during the past year were randomly chosen. their medical records were retrieved and whether they died while hospitalized was noted. it was found that on average, hospitals (26 of them) in which health care information is gathered and stored on computers had a lower patient death rate than hospitals (9 of them) that still rely on the \paper\ system (using paper forms and handwritten notes).
part i
what kind of study is this?
a. an observational study.
b. an experiment.
c. none of the above.
part ii
what sampling method was employed in selecting the 17500 patients?
a. simple random sampling.
b. stratified random sampling.
c. multistage sampling.
d. systematic sampling.
part iii
which of the following is the population of interest to the study investigator? choose the most appropriate answer.
a. all hospitals in texas.
b. all patients who were admitted to the 35 selected hospitals in texas.
c. the 35 texas hospitals that were selected in the study.
d. the 17500 patients whose medical records were retrieved in the study.
part iv
which of the following statements is correct about the average patient death rate of the 26 hospitals in which health care information is gathered and stored on computers?
a. it is a variable of interest.
b. it is a statistic.
c. it is a parameter.
part v
mr. prudence read about the study results and concluded from there that hospitals should adopt computerized automation of notes and records because it increases patient’s chance of survival. which of the following is a correct statement about mr. prudence’s conclusion?
a. it is a valid conclusion because the study was based on a very large number of patients.
b. it is a valid conclusion because the study results showed that hospitals which use computerized systems have a lower patient death rate.
c. it is an invalid conclusion because this study does not necessarily prove a causal relationship between the use of computerized system and hospital mortality.
d. both a) and b).
note: you can earn partial credit on this problem.

Explanation:

Part I

In an observational study, researchers observe and measure variables without manipulating them. Here, the investigator just observes hospital systems (computerized or paper) and patient mortality, no intervention. An experiment would involve manipulating a variable (e.g., assigning hospitals to use computerized systems), which isn't done here. So it's an observational study.

Multistage sampling involves multiple stages. First, hospitals in Texas are randomly sampled (stage 1). Then, within each sampled hospital, 500 patients are randomly chosen (stage 2). Simple random sampling would be sampling patients directly from all patients in Texas without stratifying by hospitals. Stratified sampling would involve dividing the population into strata (e.g., different hospital types) and sampling from each. Systematic sampling involves selecting every k-th element. Here, two stages (hospitals then patients) make it multistage.

The study aims to investigate the association between computerized systems and hospital mortality in Texas hospitals. So the population of interest is all hospitals in Texas (the group we want to make inferences about). The selected patients or hospitals are samples, not the population.

Answer:

A. An observational study.

Part II