AP Psych research Methods

Case Study

• One person or group is studying in dept

• Sometimes we don't have access to a lot of people with certain rare conditions

• It's hard to generalize to others when you only study one person

Naturalistic Observation

• Jane goodall and chimpanzee

• The researcher goes into someone's natural environment.

• Observing and recording only

  • Like you're invisible

• No manipulation

• Describe behavior, not explain it.

Meta Analysis

• a statistical technique that combines and analyzes the results from many different studies on the same topic or question to produce a single, overall estimate of the effect. 

• provides a "big picture" view by statistically pooling the data from individual studies to reveal the overall size and consistency of an effect, offering a more powerful and evidence-based conclusion than any single study alone. 

Correlation

• A measure of the extent to which two factors change together and thus of how well either factor predicts the other.

• Relationship between two variables

  • How well does A predict B

positive correlation

• as one variable goes up, the other goes up (vice versa; it can be the same with down) (height and weight on kids' growth charts)

  • When you grow, you should be growing taller and gaining weight

negative correlation

• as one variable increases, the other variable goes down (college alcohol consumption and GPA)

Correlation and causation 

• You cannot say correlation does not equal causation

• You can say there is a RELATIONSHIP (positive or negative) or no relationship

  • Example: amount of study and grades 

Correlation coefficient

• Strength of the correlation is measured by the correlation coefficient, a statistical index of the relationship between two variables (from -1.0 to +1.0).

• The closer to +1 or -1, the stronger the relationship (between .95 very strong)

  • -92 and 85. -92 is stronger

Scatter plots

• a graphed cluster of dots, each of which represents the values of two variables 

  • The slope suggests the direction of the relationship 

  • The amount of scatter suggests the strength of the correlation – here, there is no relationship – Height and Temperament (personality).

Experiment

• a research method where an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable).

• Can determine cause and effect! 

Independent Variable

• the variable whose effect is being studied.

• What is being manipulated

Dependent Variable

• the variable that may change in response to the independent variable.

• What is being measured

• New anxiety medication and symptoms of anxiety. 

Operational Definition

• is a carefully worded statement describing the exact procedures (operations) used in a research study.

• Measurable and manageable! We want to make sure others can replicate.

• Human Intelligence – IQ test score

• Stress – score on PSS (Perceived Stress Score)

Control Group

• Does not receive the treatment

• Serves to evaluate the effect of the treatment.

Random Sampling

• A group of participants is selected from a larger population, where every individual in the population has an equal and independent chance of being chosen. 

• The goal of random sampling is to create a sample that is representative of the entire population, allowing researchers to generalize their findings to that broader group. 

Random Assignment

• Randomly assign participants to either the experimental or control groups by chance.

• Equalizes the two groups

• Reduces preexisting differences between the groups (confounding variables). 

Representative Sample

•  subset of a larger group (a population) that accurately reflects the characteristics of that whole group

Doble Blind procedure

• procedure where both the participants and the research staff are ignorant (blind) about whether the participants have received the treatment or the placebo. 

• Limits Experimenter Bias

  • Commonly used in drug-evaluation studies

Placebo effect

•  experimental results caused by expectations alone.

• Any effect on behavior caused by giving a substance or condition, which the recipient assumes is an active agent.

Social desirability Bias

•  tendency for people to provide answers that may be dishonest so they will look good.

A confounding variable

•  a factor other than the independent variable that might produce an effect in an experiment.

Qualitative Data

•  cannot be translated to numbers (interviews most common).

Qantitative Data

• numerical data (Likert scales 1-5) Think quantity/amount.

Standard deviation (definition only, not formula)

• a computed measure of how much scores vary/differ around then mean score. (don't need to know the formula)

Statistical Significance

• You are trying to determine the likelihood that your result was due to your independent variable, rather than just chance.  

• To be statistically significant, you want your statistic to be as close to p=.05  What does this mean?

• Need to know p=.05 

• 5% likely the results are due to chance

• 95% Sure that the IV caused the DV

Effect Size

the strength of the relationship between two variables. In other words,  the larger the effect size, the more one variable can be explained by another

Normal curve

• The percentages are going to be the same 

• By the numbers (55-145) will always change because of the data

• A symmetrical, bell-shaped curve that describes the distribution of many types of data.

• In a normal distribution the mean, median, and mode are ALL the same number. 

Informed Consent

• participants should be told enough to enable them to choose whether they wish to participate

Informed Assent

•  need agreement from those under 18 or cognitively impaired.

Deception

• It's okay, but must debrief.

• After the experiment, the researcher debriefs the participants, explaining the study, including its purpose and any deception used

Debriefing

post-study when the researchers explain the true purpose of the Study to the participants, especially if deception was used to obtain informed consent and address any confusion

Positive and negative skew