Research Design AP Psych (Yellow packet)

Hypothesis

Tentative explanation; must be FALSIFIABLE; able to be supported or rejected

Operational definition

Clear, precise, quantifiable definition of your variables- allows replication and collection of reliable data

Qualitative data

Descriptive data (eye color)

Quantitative data

Numerical data; IDEAL and necessary for stats

Population

Everyone the research could apply to

Sample

The people (or person) specifically chosen for your study

Correlation

Identify relationship between 2 variables

Advantages of correlation

Useful when experiments are unethical

Disadvantages of correlation

Correlation does not equal causation

Directionality prolem

Which direction does the correlation go?

3rd variable problem

Different variable is responsible for relationship (ice cream and murder)

Positive correlation

Variables increase and decrease together

Negative correlation

As one variable increases the other decreases

The stronger the ____ the stronger the ____ regardless of?

The stronger the number the stronger the relationship REGARDLESS of the positive or negative sign

• Cannot be < or > than 1

Stronger relationships equals?

Stronger relationships = tighter clusters on graph

Experiments

Purposefully manipulate variables to determine cause/effect

Advantages of experiements

Only type that establishes cause and effect

Disadvantages of experiments

Can be unethical, too artificial

Independent variable

Purposefully altered by researcher to look for effect

Experimental group

Received the treatment (Part of the Indep variable); can have multiple experimental groups

Control gorup

Placebo, baseline (part of indep variable); can only have 1

Dependent variable

Measured variable (is DEPENDENT on the independent variable)

Placebo effect

Any observed effect on a behavior that is “caused” by the placebo (shows effectiveness of experimental treatment)

• Usually fixed with blinded studies

Double-blind

Experiment where neither the participant or the experimenter are aware of which condition people are assigned to (drug studies)

Single-blind

Only participant blind- used if experimenter can’t be blind (gender, age, etc)

Confound

Error / flaw in study that is accidentally introduced (can be called a confounding variable)

Random assignment

Assigns participants to either control or experimental groups at random- increase chance of equal representation among groups (spreads the lefties across both groups); allows you to say cause/ effect

Naturalistic observation

Observe people in their natural settings

Naturalistic Observation advantages

Real world validity

Naturalistic observation disadvantages

No cause and effect

Case study

Studies ONE person (usually) in great detail

Case study advantages

Collect lots of info

Case study disadvantages

No cause/effect

Meta-analysis

Combines multiple studies to increase sample size and examine effect sizes

Descriptive stats

Show shape of data

Measures of Central Tendency

• Mean

• Median

• Mode

Mean

Average (use in normal distribution)

Median

Middle number (use in skewed distribution)

Mode

Occurs most often

Bimodal

Has 2 modes, usually indicates good bad scores

Skews

Created by outliers

Negative skew

Mean is to the left (negative side), mode is to the right

Positive skew

Mean is to the right

Measure of variation

• Range

• Standard deviation

Range

Distance between smallest and biggest numbers

Standard deviation

Average amount the scores are spread from the mean (bigger number = more spread)

Inferential statistics

Establishes significance (meaningfulness)

Statistical significance

Results not due to chance, experimental manipulation caused the difference in means

• p<0.5 = statistical significance, smaller = better

Effect size

Data has practical significance - bigger = better

Ethical guidelines

• Confidentiality

• Informed consent

• Informed assent

• Debriefing

• Deception

• Protection from harm

Confidentiality

Names kept secret

Informed consent

Must agree to part of the study

Informed assent

Minors AND their parents must agree

Debriefing

Must be told the true purpose of the study (done after for deception)

• Deception must be warranted

Protection from harm

Mental/ physical

Surveys

Usually turned into correlation

• Subject to self report bias

Self report bias

Errors when collecting survey data to social desirability and wording effects

Social desirability

People lie to look good

Wording effects

How you frame the question can impact your answers

Random sample (selection)

Method for choosing participants for your study, everyone has a chance to take part, increases generalizability

Should you mix random sample and random assignment?

DO NOT MIX random sample and random assignment

• Sample = generalize

• Assignment = cause/ effect

Representative sample

Sample mimics the general population (ethnic, gender, age)

Convenience sample

Select participants on availability; less representative and less generalizability this way

Sampling bias

Sample isn’t representative, due to convenience sampling

Cultural norms

Behaviors of a particular group can influence research results

Experimenter bias/ participant bias

Experimenter/ participant expectations influences the outcomes

Cognitive bias

Bias in thinking/ judgement

Confirmation bias

Find info that supports our preexisting beliefs

Hindsight bias

“I knew it all along”

Overconfidence

Overestimate our knowledge/abilities

Hawthorne effect

People change behavior when watched

What does research need?

Research needs peer review when watched