You are reviewing a randomized controlled clinical trial and wonder whether stratified randomization, which the trial used, was likely to improve internal validity. This approach might be particularly helpful if:

Hello. You forgot to enter the answer options. The options are:

A. The study includes many patients.

B. One of the baseline variables is strongly related to prognosis.

C. Assignment to treatment group is not blinded.

D. Many patients are expected to drop out

E. An intention-to-treat analysis is planned.

B. One of the baseline variables is strongly related to prognosis.

Explanation:

Stratified randomization should be used whenever an experiment requires strong balance and a stable relationship in all baseline variables. In this way, the elements participating in the experiment are classified into extracts, as they are added to the experiment and in relation to the characteristics they present.

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."