Question

4. Below are several examples of research. For each one, decide if it involves random assignment or random sampling. [provide your answer and then explain in two to three sentences for each one]

   a. A law center selects 900 Civil Court records at random from the archive to investigate the effect of having versus not having legal representation (a lawyer) on the outcome of the case.

   b. A clinic recruits drug users and divides them, randomly, into two groups to test the effectiveness of a new prevention therapy.

   c. A government statistical agency takes a probability sample of the nation’s public school students and then randomly administers two different versions of a reading test to compare their difficulty.

Answer 1

(a)

A law center selects 900 Civil Court records at random from the archive to investigate the effect of having versus not having legal representation (a lawyer) on the outcome of the case.

It involves random sampling because the selection of 900 Civil Court records is based on chance and every element of the population has a non-zero probability of being selected.

(b)

A clinic recruits drug users and divides them, randomly, into two groups to test the effectiveness of a new prevention therapy.

it involves random assignment because the drug users are divided randomly to ensure that each drug userhas the same opportunity to be assigned to the two groups.

(c)

A government statistical agency takes a probability sample of the nation’s public school students and then randomly administers two different versions of a reading test to compare their difficulty.

it involves random sampling and random assignment because first a probability sample of the nation’s public school students is taken and then randomly administered two different versions of a reading test to compare their difficulty.