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Q. 1 When would you use stratified randomization? a) To assure balance in 1-2 ba

ID: 2929979 • Letter: Q

Question

Q. 1 When would you use stratified randomization?

a) To assure balance in 1-2 baseline characteristics in a small trial

b) To assure balance in all baseline characteristics in a large trial

c) To assure a random sample of participants with all strata represented

d) None of the above

Q.2

In the context of clinical trials, Type 1 error would lead you to

a)Promote worthless treatment

b)Miss an existing treatment effect

c)Ignore the p-value

d)None of the above

Q.3 In the context of clinical trials, beta error would lead you to

a)Promote worthless treatment

b)Miss an existing treatment effect

c)Ignore the p-value

d)None of the above

True or false

1. As alpha level increases, the required sample size increases

2. As desired power decreases, the required sample size increases

3. As the difference worth detecting increases, the required sample size increases

4. As the Type II error decreases, the required sample size increases

5. Because of its randomness, simple randomization guarantees equally sized treatment groups

6. Randomization ensures a random sample of the study population

7. Blocked randomization ensures treatment groups are comparable on baseline prognostic factors

8. Baseline assessment of age can be affected by ‘regression toward the mean’

9. Power is greater in one-tailed tests than in comparable two-tailed tests

10. Sample size affects the generalizability of clinical trial results

Explanation / Answer

We are allowed to do 1 question at a time. Post again for second question.

1) C option

Stratified randomization forces investigators to identify subgroups before the start of a study. As importantly, when used with blocking, stratification helps to assure that treatment assignments within subgroups are balanced. Each subgroup becomes a small trial.

The principal reasons for using stratified random sampling rather than simple random sampling include: