Randomization strengthens an experimental study in which of these ...

[Yolanda]

Randomization strengthens an experimental study in which of these ways?
 
  a. It reduces the risk that a subject will be harmed by participation in the study.
  b. It ensures that the experimental group and the control group have the same number of participants.
  c. It allows the study to proceed without the researcher knowing which group is the experimental treatment group.
  d. It increases the likelihood that the differences in outcomes between the groups are not related to chance alone.

Question 2

Random assignment of subjects to experimental and control groups has which of these effects?
 
  a. Minimizes mortality within groups
  b. Maximizes variance between groups
  c. Decreases systematic bias
  d. Increases selection bias

[olderstudent]

Answer to Question 1

ANS: D

Feedback
A Randomization does not protect a research subject from harm.
B Sampling techniques such as quota sampling ensure equal group size, not randomization.
C Randomization does not blind the researcher to treatment group versus control group.
D Randomization helps to ensure that any group differences that emerge in a study are related to the treatment condition and not to chance alone.

Answer to Question 2

ANS: C

Feedback
A Randomization has no effect on mortality (dropout rate).
B Randomization minimizes pretreatment variance between groups, rather than maximizing variance. This helps to ensure that posttreatment differences are related to the independent (treatment) variable alone.
C Random assignment to groups helps to ensure that other (extraneous) variables that could affect changes in the dependent variable are equally distributed within groups, thus reducing systematic bias.
D Randomization reduces selection bias, rather than increasing it.

[Yolanda]

Gracias!

[ricroger]

TYSM