Controlling variability in Experimental Research

Question 1

When coducting an experimental research study, an experiemnter wants a design that will maximize variability in the dependent variable that is due to the____,control variability due to____, and minimize variability due to______.

Answer 1

independent variable; extraneous variables(systematic error); random error

Question 2

Experimental variability or variability in the dependent variable that is due to the____variable is maximized when groups are made different as possible with respect to that variable while variability due to____error is minimized by ensuring thatrandom fluctuations in subjects,conditions, and measuring instruments are eliminated or equalized among all treatment groups.

Answer 2

independent;random

Question 3

A number of techniques are used to control the effects of extraneous variables, which are irrelevant to the research hypothesis but correlate withthe____variable.

Answer 3

dependent

Question 4

Randomization,or the random__ of subjects to different levels of the indepedent variable,is considered the most powerful method of control because it helps ensure that groups are initially____with regard to all known and unknown extraneous variables.

Answer 4

assignment; equivalent

Question 5

Matching is useful for controlling an extraneous variable when the number of subjects is too___to guarantee that random assignment will equalize the groups in terms of an extraneous variable.

Answer 5

small

Question 6

Blocking is similar to matching except that subjects are not individually matched but are____in terms of their status on the extraneous variable and subjects within each___are randomly assigned to one of the treatement groups.

Answer 6

blocked(grouped); block

Question 7

The ANCOVA or other statistical technique can be used to statistically___the effects of an extraneous variable.

Answer 7

remove