CADV 380

interrupted time series

a design in which treatment in an independent event, such as a historical event. -between subjects design

frequecy distribution

a graph of a distribution showing the frequency of each response in the distribution

standard deviation

a measure representing the average difference between scores and the mean of a distribution

Pre test-Post test

a measurement is taken before and after an event or treatment -within subjects design(same group of people).

distribution

a set of scores, likely to be a range between low and high values of the measurement

inferential statistics

a set of statistical procedures used by researchers to test hypotheses about the population

experimental designs

a type of research design that involves manipulation of an independent variable, and a measurement of a dependent variable, allowing control of extraneous variables that could affect results

median

middle score in a distribution such that half of the scores are above and half are below

data

numbers associated with the measurements from each individual in the study

informed consent

obtaining consent from participants for participation in research after they have been informed about the purpose, procedure, and risks

order effects

occur when the order in which participants experience conditions in an experiments affect the results of a study.

testing effects

occurs when participants are tested more than once in a study with early testing affecting later testing

central tendency

one way to summarize a data set; representation of a typical score in a distribution (mean, median, mode)

freedom of coercion

participants able to choose to participate; free to stop participating at any time with no consequences

random assignment

participants are randomly assigned to levels of the independent variable in an experiment to control for individual differences

subject mortality

people opting out of study

p-value

probability value associated with an inferential test that indicated the likelihood of obtaining the data in a study due to chance (the null hypothesis is true)

ethics

rules of conduct recognized in respect to a particular class of human actions or a particular group, culture, etc.

longitudinal design

same children tracked over time. -within subjects -developmental design considerations: subject mortality, history & testing effects

stratisfied sampling

sample chosen form the population such that proportion of individuals with a particular characteristic is equivalent in the population in the sample

cluster sampling

sample chosen randomly from clusters identified in a population

simple random sampling

samples chosen randomly from the population such that each individual has an equal chance of being selected

nuremberg code

set of guidelines developed for research with human subjects based on info gained during the nuremberg trials after WWII

counterbalancing

a control used within subjects experiment where equal number of participants are randomly assigned to different orders of conditions

Quasi-Experimental Designs

a type of research design where a comparison is made as in an experiment, but no random assignment occurs types: pretest posttest, interuppted time series, longitudinal and cross sectional

independent variables

a variable that is manipulated by the researcher such that the levels of a variable change across or within subjects

dependent variable

a variable that is measured for each level of the independent variable (expecting changes in values from one level of manipulation to another)

main effect

an effect in the independent variable on the dependent variable regardless of levels of other independent variables

interaction

an effect of one independent variable on the dependent variable which changes from one level of the independent variable to the other level

factorial design

an experiment that includes more than one independent variable

confounding variable

an extraneous variable present in a study that may affect results

extraneous variable

anything in a study not part of the manipulation or measurement (time of day, gender etc)

cross sectional

different children compared at different ages -between subjects considerations: cohort effects

history effects

events occur during the course of a study to all or individual participants that can result in bias

cohort effects

group effects

within subjects

independent variable where each participant experiences every level of the variable

between subjects

independent variable where each participant experiences only one level of the variable

benefit risk factor

information from study must outweigh the risks of harm that the participant incur as part of the study.

mean

is the calculated average of the scores in a distribution

Qualitative

levels of independent variable are different categories/ classes

quantitative

levels of independent variable are different values of measurement

analyses/statistics

mathematical methods for summarizing or interpreting data

marginal mean

means of independent variable one collapsed across levels of independent variable two

descriptive statistics

measures that help summarize the data set; describes the sample

range

the difference between the lowest and highest scores of a distribution

sampling error

the difference between the observations in a population and in the sample that represents that population in a study

internal validity

the extent to which changes in your dependent variable result from changes in levels of your independent variable (you can make causal conclusions)

mode

the most common score of the distribution

alpha level

the probability level used by researchers to indicate the cut off level (highest level) of error that will allow them to reject the null. (usually .05 or .01)

variability

the spread of scores of a distribution

variance

the standard deviation of a distribution squared

regression toward the mean

when participants score higher or lower than their average, they are likely to score near their average the next time they are tested i.e. wheaties effects

alternative hypothesis

your treatment has an effect on the dependent variable

null hypothesis

your treatment has no effect on the dependent variable