Intro to Research Design

Question 1

Primary vs Secondary Source

Answer 1

Primary source - document provided directly by the author

Secondary source - Reviews, textbooks, etc

Question 2

Independent variable

Answer 2

Condition that will change a given outcome

Question 3

Dependent variable

Answer 3

Outcome variable dependent on the independent variable

Question 4

Operational definitions

Answer 4

Definition of variable according to unique meaning within the study (normallly dependent variable)

Ex) Pain intensity, variability in stride velocity

Question 5

Research objectives

Answer 5

• to evaluate measuing instrument
• to descrive population or clinical phenomena
• to explore relationships
• to compare between groups or conditions

Question 6

Research hypothesis

Answer 6

• statement that predicts relationship between IV and DV
• statement of researcher’s expectations

Question 7

Null hypothesis

Answer 7

• Statistical hypothesis
• States that “no difference” occurs between variables

Question 8

Sampling bias

Answer 8

When sample over or under-estimates the characteristics being investigated

Question 9

How to reduce sampling bias

Answer 9

• Random Sampling
• Well defined inclusion/exclusion criteria

Question 10

Three characteristics of experiments

Answer 10

1. Manipulation of variables
2. Random assignment
3. Control group

Question 11

Intention to treat analysis

Answer 11

Statistical analysis used when handling incomplete data. It minimizes bias assicated with missing data.

Question 12

How to exert control without it being a true experiment

Answer 12

1. Homogeneous subjects
2. Blocking
3. Matching
4. Repeated measures

Question 13

Homogeneous Subjects

Answer 13

Subjects identical on a potentially confounding variable

Disadvantage - results only generalized to specific types of people

Question 14

Blocking

Answer 14

Build extraneous variables into study design by using them as IV

Ex) Age blocked by decade

Question 15

Matching

Answer 15

Match subjects based on specific characteristics

Ex) For every female gymnist, I will get one male gymnist

*Matching is during selection, blocking is after*

Question 16

Repeated Measures

Answer 16

• All levels of the IV are experienced by all subjects
• Subjects are matched to themselves
• Efficient method for controlling potential inter-subject differences

Question 17

Threats to validity heirarchy

Answer 17

1. Statistical conclusion validity
2. Internal validity
3. Construct validity
4. External validity

Question 18

Statistical Conclustion Validity

Answer 18

If the statistics are incorrect, then the whole study is considered invalid

Question 19

Internal Validity

Answer 19

Are changes in the DV due to factors other than manipulation of the IV?

• History - events between tests?
• Maturation - subject changes between tests
• Attrition - subject drop out
• Testing effects - the act of testing may change person’s response
• Order effects
• Instrumentation

Question 20

Construct Validity

Answer 20

The operation (measurable) represents a construct (not-measurable).

How well is a variable “operationally defined”

Question 21

External Validity

Answer 21

Can results be generalized to people/setting/times different from those used in the study?

Question 22

Single Factor Experimental Design

Answer 22

Pretest-posttest control group

• Random
• Observation - Intervention - Observation
• Observation - control - Observation

Posttest only

• Random
• Intervention - Observation
• Not practical to give pretest (education)

Question 23

Multi-factor Experimental Design

Answer 23

Factorial

• Two or more IVs
• AxB factorial design – 2 IVs, “A” levels in IV1, “B” levels in IV2
• Ex) “A” walking speeds, “B” environments

Question 24

Repeated Measures

Answer 24

1-way

• Time as IV = Observation - Intervention - Observation - Observation - Observation…
• Treatment as IV = Intervention - Observation; Intervention2 - Observation; Intervention3 - Observation…

Mixed

• Two or more IVs
• One variable is repeated across subjects
• One variable has independent groups

Question 25

Quasi-Experimental Designs

Answer 25

* 1-Group Pretest-Posttest -- no control, no correlation * Nonequivalent Pretest-Posttest -- no randomization * Nonequivalent Posttest only

Question 26

Exploratory Research

Answer 26

Systematic investigation of relationships among 2+ variables

Question 27

Observational research

Answer 27

* Naturally existing data * No manipulation of variables

Question 28

Retrospective vs Prospective

Answer 28

Retrospective * Examination of data collected in the past * Some questions can only be answered retrospectively * Lack of control/ missing data Prospective * Measurement in present and future * greater control, greater reliablility * great time, expense

Question 29

Longitudinal vs Cross-sectional

Answer 29

Longitudinal * Follow group over time * document change in specific individuals * long term commitment, little flexibility * threats to internal validity Cross-sectional * Study stratified group at point in time to draw conclusions * less costly, subjects only tested once * potential selection bias, cohort effets

Question 30

Prevalence vs Incidence (Epidemiologic studies)

Answer 30

Prevalence (P) * Ratio of existing cases to total population * estimates probability that an individual will have the condition at any point in time Incidence (CI) * Ratio of new cases to total population * Estimates risk of developing condition at any point in time P is greater than or equal to CI

Question 31

Vital Statistics

Answer 31

Birth rate and Death rate If Birth rate is higher than death rate, population is growing

Question 32

Descriptive Research

Answer 32

* Developmental (change over time) * Normative - describe standard values for characteristics of specific populations