2/22/10 Comm402 Chapter 3 Dependent Variables and Independent variables o In an experiment the independent variable (IV) is the variable that is varied or manipulated by the researcher and the dependent variable (DV) is the response that is measured In non-experimental research, where there is no experimental manipulation the IV is the variable that logically has the effect on a DV. For example in the research on cig smoking and lung cancer cig smoking which has been
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Identifying IVs and DVs o There will a statistically significant difference in grad rates of at risk high school seniors who participate in an intensive study program as opposed to at risk high school seniors who do not participate in the intensive study program IV- participation in intensive study program DV- graduation rates
Validity and Reliablitiy o Validity determines whether the research truly measures that which it was intended to measure or how truthful the research results are. Researchers generally determine validity by asking a series of questions and will often look for the answers in the research of others (joppe, 2000, p.1) o Valid suverys they are accurate
The extent to which results are consistent over time and accurate representation of the total population under study is referred to as reliability and if the results of a study can be reproduced under a similar methodology then the research instrument is considered Reliable reliable. given to all adults generate same results
Models should contain o o Truth Beauty means that their simple Simplicity
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Fertility it can generalize all different types of situations Surprise
Justice model has certain positive influence on society
Critical experiments o o We prefer to compare alternative models rather than accept or reject a single model A critical experiment is an observation that will allow us to choose from alternative reasonable models.
A simple childhood theory of personality says that a persons basic personality are formed between the time is born and age five and that this basic personality and character remain substantially unchangeable for the remainder of his life. A simple conditioning and growth theory of personality says that basic personality and charter are formed continuously by his daily experience. Hence he may change over time in response to changing environment and it is possible to change adult personality and behavior radically. o o o o Make up 2 facts (predictions) that, if they were true, would tend to confirm the childhood theory Do the same to confirm the conditioning growth theory Make up a critical fact that, if it were true, would simultaneously contradict one theory and support the other. It should be an observable fact in a natural experiment Examine the relative justice of two theories assuming they are equally correct