Which of the options in Figure 32.4 is likely to have the smallest SD?

1. P
   
2. Q
   
3. R
   
4. All have same SD

What would be the best test to decide if the mean age of two groups is different?

1. Unpaired t-test
   
2. Paired t-test
   
3. Chi squared test
   
4. Linear regression

A group of 40 patients is given a treatment. Measurements of heart rate are taken before and after. What would be the appropriate test to determine if the treatment was effective?

1. Unpaired t-test
   
2. Paired t-test
   
3. Chi squared test
   
4. Linear regression

Treatment “A” cured 40% of the patients and treatment “B” cured 70% of the patients. What would be the appropriate test to determine if the two treatments are different?

1. Unpaired t-test
   
2. Paired t-test
   
3. Chi squared test
   
4. Linear regression

The relationship between age and E/A velocity ratio can be studied best with which test?

1. Unpaired t-test
   
2. Paired t-test
   
3. Chi squared test
   
4. Linear regression

Measures of population description include which of the following?

1. Measures of central tendency and dispersion
   
2. Mean and median
   
3. IQR and range
   
4. Median and SD

The effects of treatments A and B are compared on mortality in a randomized trial. At the end of 2 years the mortality with treatment A was 15% and treatment B was 12%. What was the relative risk reduction with treatment B?

1. 3%
   
2. 20%
   
3. 10%
   
4. 25%

In Question 32.10, what was the absolute reduction with B compared with A?

1. 3%
   
2. 20%
   
3. 10%
   
4. 25%

In Question 32.10, what was number needed to treat with B compared with A to save a life over 2 years?

1. 33
   
2. 7
   
3. 8
   
4. 100

A noninvasive diagnostic test to sort out a symptom is most productive in which patient groups?

1. Low probability of disease
   
2. Intermediate probability of disease
   
3. High probability of disease
   
4. All of these groups

A group 100 patients with documented disease and 100 without disease got a diagnostic test to detect that disease. Among those with disease 80 had a positive test, and among those without disease 20 had a positive test. What is the sensitivity of the test?

1. 80%
   
2. 20%
   
3. 40%
   
4. 50%

In the example in Question 32.14, what is the specificity of the test?

1. 80%
   
2. 20%
   
3. 40%
   
4. 50%

In the example in Questions 32.14 and 32.15, what is the positive predictive value?

1. 80%
   
2. 20%
   
3. 40%
   
4. 50%

In the example in Questions 32.14 and 32.15, what is the negative predictive value?

1. 80%
   
2. 20%
   
3. 40%
   
4. 50%

Which of the following measures are affected by pretest probability of disease prevalence in which the test is performed? More than one choice may be correct.

1. Sensitivity
   
2. Specificity
   
3. Positive predictive value
   
4. Negative predictive value
   
5. All of the above
   
6. None of the above

Which of the following test characteristics are ideal for screening of disease?

1. High sensitivity, low cost, minimal risk
   
2. High specificity, low cost, minimal risk
   
3. Either A or B
   
4. Neither A nor B

Which test characteristics are ideal for confirming the presence of a disease?

1. High sensitivity, low cost, minimal risk
   
2. High specificity, low cost, minimal risk
   
3. Either A or B
   
4. Neither A nor B

Which of the following will false positives increase with?

1. Higher pretest probability
   
2. Lower pretest probability
   
3. Intermediate pretest probability
   
4. None of the above

As the test positivity criterion gets more stringent (e.g., increasing ST depression requirement to 2 mm instead of 1 mm), which of the following will happen to the test?

1. Increase in sensitivity and specificity
   
2. Decrease in sensitivity and specificity
   
3. Decrease in sensitivity and increase in specificity
   
4. Increase in sensitivity and decrease in specificity

What is the positive likelihood ratio (LR+) of a test with 90% sensitivity and 90% specificity?

1. 1
   
2. 5
   
3. 9
   
4. 90

The pretest probability of disease based on risk factors and presentation in an individual is 10%. If the test described in Question 32.23 is positive, what would be the probability of disease?

1. 30%
   
2. 50%
   
3. 90%
   
4. 99%

You want to test if treatment “X” prolongs survival in a disease under study. What would be the best study design?

1. A double-blind randomized controlled clinical trial with power >0.8, an outcome adjudication committee, and safety monitoring committee
   
2. Single blind trial so that you can monitor to make sure that the patient is not harmed
   
3. A smaller trial with outcome surrogates
   
4. A nonrandomized trial with propensity score matching

In the trial in Question 32.25, 1800 patients were enrolled, 900 in the active treatment arm and 900 in the placebo arm. At 2 years there were 200 deaths in the treatment arm and 250 in the placebo arm. The groups are well balanced in terms of baseline characteristics. What is the best approach for outcome analysis?

1. Kaplan–Meier analysis
   
2. Student’s t-test
   
3. Chi squared test
   
4. None of the above