1. ## Statistics Problem

I've literally tried answering this over 35 times and I just can't seem to get it. I included my answers below. If possible, can you provide some clarity.
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

What graphical display is appropriate for comparing the distribution of patient death rates between hospitals that use computer systems and those that rely on the paper system?
A. A scatterplot.
B. A bar chart.
C. A stem-and-leaf display.
D. Side-by-side boxplots.
Part VI

Mr. Prudence read about the study results and concluded from there that hospitals should adopt computerized automation of notes and records because it increases patients 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).

2. ## Re: Statistics Problem

I forgot to include my answers but they are
1.A
2.A
3.B
4.D
5.B
6.D

3. ## Re: Statistics Problem

Hey megarust.

I think it might be better to look at the reason behind the answer and not so much the answer itself.

I'll start off with the first question.

The experimental study controls a limited set of variables and has variation in those random variables where-as observational studies do not allow variation [i.e. to control relationships or fix values in the actual values being recorded].

Based on this what do you think it is?

4. ## Re: Statistics Problem

Based on that definition, it would be experimental since there is variation.