chapter 5 (quiz 2)

Question 1

Experiment Basics: 3 Properties of a True Experiment

Answer 1

1. One or more IV’s (what’s being manipulated, ex. amt of dose)
2. One or more DV’s (what’s being measured/effect)
3. Experimental Control (randomly assignming PT to conditions), control extraneous variables

Question 2

Types of IVS

Answer 2

amount, type, presence/absence

Question 3

Types of DVs

Answer 3

speed, accuracy (% correct), rate (frequency), degree (amount. ex: salivation)

Question 4

Experimental Control

Answer 4

1. * Control over Assignment of PT to Conditions (essential)

2. control over extraneous variables (unwanted variables)
- Extr. Variables can produce 2 types of effects
~unsystematic/error
variance (variance in
scores across all your
groups)
~systematic: experiment is
worthless, differences in
group like temperature,
noise, could affect
experiment

Question 5

ways to control extraneous variables

Answer 5

hold unwanted variables constant: ex. keep room same temp, white noise generator in both rooms

block: ex. questionnaire, but can only block one thing (ie. how much sleep each person in group got

**randomize: randomly assign PT to groups

Question 6

variation in experiments

Answer 6

1. variance due to IV (we want this)
2. variance due to confounding variable (minimize/eliminate this)
3. error variance (differences within each group)

Question 7

within-subjects design & advantages

Answer 7

participants receive all levels of the IV(s)

reduces error variance, requires fewer PTs, greater statistical power

Question 8

within-subjects design: disadvantages

Answer 8

greater demands on PTs (time & effort), potential carryover effect (ex. getting tired from mile 1-3) but can be minimized with counterbalancing (diff order)
- complete counterbalancing: equal number of PT in every possible order of conditions
- incomplete counterbalancing: complete A first once, 2nd once, 3rd once, etc.

Question 9

between subjects design & adv/disadv

Answer 9

participants receive only one level of the IV(s)

advantages: only way to test some variables (like surgery), no carryover effects

disadvantages: greater error variance, possibilities of non-equivalent groups

Question 10

mixed designs

Answer 10

Two or more IVs, at least one between-subjects variable and at least one within-subjects variable

Question 11

types of validity

Answer 11

1. **Internal Validity: did the levels of the IVs cause changes in the DVs?
2. External Validity: do the results of the experiment generalize to other contexts?
3. Construct Validity: did the researcher use a good operational definition?
4. Statistical Validity: did the researcher use the correct statistics?