Week 4 Validity pt 2 + experimental designs

Question 1

threats to external validity

Answer 1

interaction of….

• selection and treatment
• setting and treatment
• history and treatment

Question 2

selection and treatment

Answer 2

• can we generalize results beyond specific group in the study?

Question 3

setting and treatment

Answer 3

• can we generalize results beyond study setting?

Question 4

history and treatment

Answer 4

• generalize results from time A to other times

Question 5

non-experimental methods

Answer 5

• correlational studies: relationship between 2(+) measured

- correlation =/= causation

Question 6

experimental methods

Answer 6

• cause and effect relationship between IV and DV

- eliminate all influences on DV that are not IV

Question 7

6 qualities of an experiment

Answer 7

• random assignment
• extraneous variable control
• IV (experimental manipulation)
• DV (outcome measurement)
• comparing different groups
• threats to validity

Question 8

equating groups

Answer 8

making groups “equal” (individual differences)

- in practice: systematically distributing influence of extraneous variables across different conditions

Question 9

EV

Answer 9

other variable(s) that may cause changes in DV

• participant selection
• procedures
• statistics
• design

Question 10

controlling EV (6)

Answer 10

• random assignment
• pretest
• covariance
• participant matching
• homogeneous sample
• blocking variables

Question 11

random assignment

Answer 11

• eliminates/reduces systematic differences between groups

Question 12

pretest (2)

Answer 12

• measuring variable before experimental intervention

- comparing pretest and postest to see if manipulation had effect

Question 13

issues with pretest (4)

Answer 13

• time, effort, resources
• demand characteristics
• interaction w/experimental intervention
• testing effects

Question 14

covariance

Answer 14

• not all changes in DV can be explained by IV
• a covariate in statistical analyiss can reduce error variances
• more accurate representation of IV/DV relationship

Question 15

matching participants

Answer 15

• matching based on variable that can skew results (eg gender, pretest scores, etc)
• distribute ppl w/similar scores equally between groups

Question 16

homogeneous of participants

Answer 16

• choosing in advance participants who are similar on some variables (eg GPA, background)
• limits unexplained variance between groups

Question 17

blocking variables

Answer 17

creating homogeneous sub-groups -> randomly assigning participants in each sub-group to control/experiment group

Question 18

experimental intervention

Answer 18

• intentionally causes something that only one group experiences
• different groups make different experimental conditions
• condition receives different level of IV

Question 19

experimental conditions

Answer 19

• 2(+) levels
• manipulate 1(+) IV
• IVs that cannot be manipulated: age, gender, birth order, etc.

Question 20

between subjects design

Answer 20

• true experiments (pre/post test, post test)
• quasi-experiments (pre/post test, post test)
• factorial design