W2 - Research Methods

theory

• explanation of why

• under what circumstances certain things occur

  • make predicitions

  • understand relationshups between varuables

variable

• characteristic, object or event that can change

independent variable

• something that can influence something else

  • e.g., cholesterol

dependent variable

• can be changed by the independent variable

  • e.g., heart rate

mortality

• death

morbidity

• illness

• injury

• disability

prevalence

• number ofcases

incidence

• number of new cases

epidemic

• incidence of disease has increased rapidly

pandemic

• epidemic

• increased to international proportions

methods to study health psych. related variables

• experimental studies

• non-experimental studies

experiment

• controlled study

• researchers manipulate an independent variabel

• study its effect on the dependent variable

manipulate

• researcher controls level of indiependent variable

controlled

• remove confounding variables

random assignment

• equate groups before manipulation

• balances pre-existing things

• characteristics should be equal in both groups

experimental group

• group of people who receive a treatment

control group

• group of people who receieve no treatment

placebo

• inactive substance or procedure

double blind procedure

• participant and scientist are blind to which pills have the active component and who they were given to

criteria to make causal statement

1. levels of independent and dependent variable must correspond together

2. cause precedes the effect

3. all other cuases have been ruled out

non-experimental study

• no manipulation of the independent variabel

• does not provide causal evidence

types of non-expirmental studies (3

• correlational

• quasi

• genetic

correlation coefficient ®

• relationship between two variables

• as one changes, so does the other

correlational studies

• investigations of the degree and direction of two variables

positive association

• both variables move in the same direction

  • increase and increase

  • decrease and decrease

negative association

• variables move in opposite direction

  • increase → decrease

  • decrease → increase

magnitude of correlaion

• r value tells us the strength of the association

  • effect size

• interpret strength while ignoring the sign

  • -.83 is stronger than .78

quasi experimental studies

• look like experiments

• people are not randomized

independent varibale

• may or may not be manipulated

twin studies

• research on hereditary factors

• focus on differences between monozygotic and dizygotic twins

adoption studies

• compare traits of adopted children with bio parents and adopted parents

epigenetics

• chemical structures within and around DNA govern how, and how much a gene acts