Matching experimental and control groups

Question 1

how to match the overall distribution of the study

Answer 1

• exp and control groups have same distribution of extraneous variables
• match based on the frequency of occurrence of each extraneous variable

ex) same number of women and men- age range, IQ

Question 2

regression towards the mean

Answer 2

• when observing repeated measurements in the same subject, relatively high or low observation are likely to be followed by less extreme ones nearer the subjects true mean
• true problem=the need to distinguish a real change from this expected change due to the natural variation

Question 3

interactional observer bias

Answer 3

-bias affects subjects behavior

Question 4

non-interactional observer bias

Answer 4

-error of observation and recording

Question 5

Rosenthal effect

Answer 5

• experimenter factors may influence the behavior of research subjects
  ex) biosocial, psychosocial, situational variables, modeling effects, self-fulfilling prophecy

Question 6

modeling effects

Answer 6

subject behaves like experimenter

Question 7

situational variables

Answer 7

experience, familiarity with subjects

Question 8

Inter-experimenter reliability

Answer 8

• several different investigators

- replicated with different investigator

Question 9

intra-experimenter reliability

Answer 9

consistency of a single investigator