Order Research and Biostatistics Essay

Order Research and Biostatistics Essay
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Order Research and Biostatistics Essay
1. A study involving 100 patients assessed the efficacy of a high-flow nasal cannula (HFNC)
administration in preventing intubation after chest trauma. Among 40 patients who received
HFNC, 35 did not require intubation. Among the 60 patients who did not receive HFNC, 55 did
not require intubation. The statistical test MOST appropriate to determine if HFNC use is
associated with a reduction in the need for intubation is
A. Chi-square test
B. Analysis of variance
C. Log-rank test
D. A relative risk
2. An intensivist performs a study which examines the impact of a chlorhexidine bathing protocol
on the incidence of new methicillin-resistant Staphylococcus aureus (MRSA) infections in the
ICU. Based on her sample size calculation, 300 patients are needed for randomization to the
two study groups (chlorhexidine vs. standard care), to detect a clinically meaningful difference
with power of 0.8. However, due to cost constraints, only 200 patients are ultimately enrolled
in the study. Statistical testing of the data reveals a lower incidence of MRSA infection in the
chlorhexidine group compared with the standard care group (P < .001). Which of the following
statements regarding interpretation of the findings is MOST correct?
A. The chlorhexidine protocol is effective
B. The chlorhexidine protocol is not effective
C. A type 1 error is likely
D. A type 2 error is likely
3. Statistical analysis of 20 patients with acute respiratory distress syndrome shows a mean
cardiac output (CO) of 5 L/min with a standard deviation of 1 L/min. The distribution of CO in
the population is normal. Which of the following statements is MOST accurate regarding
interpretation of these data?
A. Approximately 50% of the sample population would be expected to have a CO between 4 and
6 L/min
B. Approximately 95% of the sample population would be expected to have a CO between 3 and
7 L/min
C. Of the sample patients, 10 have a cardiac output greater than 5 L/min
D. The mean and the median CO are the same in the sample of 20 patients
4. An investigator wants to compare a new noninvasive cardiac output measurement technology to
cardiac output obtained from a pulmonary artery catheter using the thermodilution technique.
Which of the following statistical methods is MOST appropriate for comparing the two
techniques?
A. Cohen’s kappa statistic
B. Correlation analysis
C. Bland-Altman analysis
D. Kaplan-Meier plot
Order Research and Biostatistics Essay
5. A study is being designed to compare the efficacy of two analgesic regimens on pain scores of
patients in the ICU. Which factor is MOST likely to increase the number of patients required to
detect a difference between the two analgesic regimens?
A. Low variability of individual responses to analgesic treatment
B. Lack of randomization of patients to treatment regimens
C. Little difference in the effectiveness of the two regimens
D. Use of blinded rather than nonblinded observers
6. An investigator wants to evaluate the impact of a new anti-inflammatory agent on survival from
septic shock. He randomizes 300 patients that develop septic shock to either receive the antiinflammatory agent together with standard care or to receive standard care alone. He follows
the two groups until ICU discharge. Which of the following is the most appropriate test to
compare survival in the two groups?
A. Log-rank test
B. T-test
C. Chi-square test
D. Wilcoxon Rank Sum test
7. Which of the following Pearson correlation coefficients represents the strongest linear
relationship between two variables?
A. 0.85
B. –0.80
C. 1.25
D. –0.95
8. An investigator wishes to perform analysis of retrospective cohort data to examine the impact of
goal-directed fluid management (independent variable) on the need for renal replacement
therapy (dependent variable) in patients suffering from major thermal injury. Potential
confounding variables which the investigator wishes to control for in the analysis are age,
baseline creatinine level, and sequential organ failure assessment score. Which method of
regression analysis is MOST appropriate for this analysis?
A. Simple linear
B. Cox
C. Multivariable linear
D. Logistic
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