6 Basics of Experimentations

Question 1

One criterion of science is replicability. Specifies the precise meaning of a variable within an experiment.
Tell others how to carry out an experiment

Answer 1

Operational definitions

Question 2

Describe exactly what was done to create the various treatment conditions of the experiment.

Answer 2

Experimental Operational Definitions

Question 3

Consistency and dependability.
Good operational definitions are reliable
If we apply them in more than one experiment, they ought to work in similar ways each time.
Hungry and Not hungry (2 conditions)
If our operational definition is reliable, we obtain similar consequences.

Answer 3

Reliability

Question 4

Consistency and dependability.
Good operational definitions are reliable
If we apply them in more than one experiment, they ought to work in similar ways each time.
Hungry and Not hungry (2 conditions)
If our operational definition is reliable, we obtain similar consequences.

Answer 4

Reliability

Question 5

Different observers take measurements of the same responses.
Agreement between their measurement.
Little agreement- measuring procedure is not reliable.

Answer 5

Interrater reliability

Question 6

Comparing scores of people who have been measured twice with the same instrument. Take the test once, then they take it again (after a reasonable interval). Reliable measure should produce very similar scores each time the person is measured.
Consistently get about the same scores on a personality test, the test is considered reliable.
Wechsler Adult Intelligence Scale (WAIS-III)- excellent test-retest reliability

Answer 6

Test-retest reliability

Question 7

Extent to which different parts of a questionnaire, test or other instruments designed to assess the same variable attain consistent results.
Scores on different items designed to measure the same construct should be highly correlated

Answer 7

Inter-item reliability

Question 8

• splitting the test into two halves at random and computing a coefficient of reliability between the scores on the two halves
  The two halves of the test should correlate strongly if the items are measuring the same variable.

Answer 8

Split-half reliability

Question 9

• correlation of each test item with every other item.

Answer 9

Cronbach’s α

Question 10

Studying the variables that we intend to study.

Answer 10

validity

Question 11

• Does the content of our measure fairly reflect the content of the quality we are measuring? Are all aspects of the content represented appropriately?
  -Racial attitudes
• Ratings from objective judges with expertise in the area of racial attitudes

Answer 11

Content Validity

Question 12

• Do our procedures yield information that enables us to predict future behavior or performance?
• Affiliation
• Subjects who said they wanted to wait with others will seat themselves closer and talk to each other
• Do not observe the overt signs of the desire to affiliate
• The measure does not have predictive validity: it does not predict what people will do.

Answer 12

Predictive validity

Question 13

• Comparative rather than predictive
• Evaluated by comparing scores on the measuring instrument with another known standard for the variable being studied
• Anxiety measure
• Compare people’s scores on our anxiety test with rating from clinical evaluations of anxiety

Answer 13

Concurrent Validity

Question 14

• Have I succeeded in creating a measuring device that measures the construct I want to test?
• Intelligence test truly measures only intelligence.

Answer 14

Construct validity