Topic 2 Threats to validity

Question 1

Threats to internal validity:

Answer 1

outside influences that can affect DV therefore alternate explanations

Question 2

Threats to internal validity: History

Answer 2

caused by events outside the lab ex: weather

Question 3

Threats to internal validity:

Maturation

Answer 3

naturally occurring process

a. control group used to show kids getting smarter because of tutor and not aging
ex: getting older

Question 4

Threats to internal validity:

Testing

Answer 4

practice effect or the test may be primed

a. Using different form of the post-test
b. Counter-balancing- equal number of participants receive each possible order of conditions

Question 5

Threats to internal validity:

Instrumentation

Answer 5

reliable instruments to measure DV or manipulate IV

a. Reliability and validity

Question 6

Threats to internal validity:

regression toward the mean

Answer 6

extreme scores regress towards the mean on the 2nd measure

a. Use control group with no treatment to see if same change happens

Question 7

Threats to internal validity:

Selection Bias

Answer 7

between subjects design

a. two groups difference may cause selection bias
i. Different effect on the DV independent of the IV

Question 8

Threats to internal validity:

Mortality Attrition

Answer 8

• subject lost or attrition or death

a. Those who drop out may be different from those who didn’t

Question 9

Threats to internal validity:

Experimenter Bias

Answer 9

experimenter unintentionally biases the results

a. Expectations may affect how they treat a group, affecting the results

Question 10

Threats to construct validity

Answer 10

Hard to achieve-(is there an alternative theoretical explanations?)

1. Loose connection between “theory” and “method”
   a. Inappropriate measures can hurt if it is capturing something other than what you are looking for, then the results are invalid

Question 11

Threats to external validity:

Answer 11

Is experiment generalizable?

1. Replication is essential to establishing external validity
   a. Is experiment the same with:
   i. Other subjects?
   ii. Other times?
   iii. Other places?

Question 12

Threats to statistical validity:

Type 1 Error

Answer 12

Factor that can lead to incorrect conclusion
a. Type 1- there is relationship when there’s not
false positive
c. Violated assumptions of statistical tests can lead to either type of error

Question 13

Threats to construct validity:

Social Factors

Answer 13

participants may act different based on their expectations

Question 14

Threats to construct validity:

Role Demands

Answer 14

Participants expectations of what an experiment requires them to do

Question 15

Threats to construct validity:

Evaluation Apprehension

Answer 15

participants tend to alter their behavior to appear as socially desirable as possible

Question 16

Threats to statistical validity:

Type 2 Error

Answer 16

b. Type 2- no relationship when there is (most common)
i. Low reliability of measures
ii. Random error
iii. Low statistical power
false negative
c. Violated assumptions of statistical tests can lead to either type of error