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The Research Process: Coming to Terms © 2011 Pearson Prentice Hall, Salkind. Describe the research process from formulating questions to seeking and finding solutions. Describe the difference between dependent and independent variables. Identify other types of variables that may interfere with the research process. Define a hypothesis and describe how it works. Discuss the value of the null hypothesis. © 2011 Pearson Prentice Hall, Salkind. Describe the differences between a null hypothesis and a research hypothesis. List the characteristics of a good hypothesis. Explain the difference between a sample and the population. Define statistical significance and explain its importance. © 2011 Pearson Prentice Hall, Salkind. From Problem to Solution All About Variables Other Important Types of Variables Hypotheses Samples and Populations The Concept of Significance © 2011 Pearson Prentice Hall, Salkind. © 2011 Pearson Prentice Hall, Salkind. Increasing our understanding of how and why we behave the way we do!! © 2011 Pearson Prentice Hall, Salkind. From Problem to Solution ◦ Noting an interesting question ◦ Stating the question in such a way that it can be answered The Language of Research © 2011 Pearson Prentice Hall, Salkind. © 2011 Pearson Prentice Hall, Salkind. Variables are a class of outcomes that can take on more than one value The more precisely a variable is measured, the more useful the measurement is © 2011 Pearson Prentice Hall, Salkind. The outcomes of a research study Depend on the experimental treatment © 2011 Pearson Prentice Hall, Salkind. Treatments or conditions under control of the researcher Levels—at least two different values of the independent variable must be present © 2011 Pearson Prentice Hall, Salkind. © 2011 Pearson Prentice Hall, Salkind. Independent variable is not confounded ◦ Levels do not vary systematically with other variables Dependent variable is sensitive to changes in the independent variable © 2011 Pearson Prentice Hall, Salkind. © 2011 Pearson Prentice Hall, Salkind. Control Variable: Has a potential influence on the dependent variable Extraneous Variable: Has an unpredictable impact on the dependent variable Moderator Variable: Variables related to independent or dependent variables, and hiding the true relationship between independent and dependent variables © 2011 Pearson Prentice Hall, Salkind. Type of Variable Dependent Definition Other Terms You Might See A variable that is measured to see whether the treatment or manipulation of the independent variable had an effect Independent A variable that is manipulated to examine its impact on a dependent variable Control A variable that is related to the dependent variable, the influence of which needs to be removed Extraneous A variable that is related to the dependent variable or independent variable that is not part of the experiment Moderator A variable that is related to the dependent variable or independent variable and has an impact on the dependent variable Outcome variable Results variable Criterion variable Treatment Factor Predictor variable Restricting variable Threatening variable Interacting variable © 2011 Pearson Prentice Hall, Salkind. © 2011 Pearson Prentice Hall, Salkind. Reflects the general problem under study Restates the general problem in a form that is precise enough to allow testing © 2011 Pearson Prentice Hall, Salkind. States that there is no relationship between the independent and dependent variables under study Ho: µ1 = µ2 ◦ Ho: Null hypothesis ◦ µ1: Theoretical average of population 1 ◦ µ2: Theoretical average of population 2 © 2011 Pearson Prentice Hall, Salkind. A starting point for analysis ◦ Accepted as true absent other information ◦ Assumes that chance caused any observed differences Provides a benchmark for comparison © 2011 Pearson Prentice Hall, Salkind. A statement of inequality A relationship exists between the independent and dependent variables • H1: X1 ≠ X2 – H1: Research hypothesis – X1: Theoretical average of population 1 – X2: Theoretical average of population 2 © 2011 Pearson Prentice Hall, Salkind. Nondirectional Research Hypothesis ◦ Groups are different, but direction is not specified ◦ H1: X1 ≠ X2 Directional Research Hypothesis ◦ Groups are different, and direction is specified ◦ H1: ◦ H1: > X1 X2 < X1 X2 © 2011 Pearson Prentice Hall, Salkind. Directly tested during research process To compare against null hypothesis © 2011 Pearson Prentice Hall, Salkind. Null ◦ Equality between variables ◦ Refers to population ◦ Indirectly tested ◦ Stated using Greek symbols (µ) ◦ Implied Research ◦ Inequality between variables ◦ Refers to sample ◦ Directly tested ◦ Stated using Roman symbols ( ) X ◦ Explicit © 2011 Pearson Prentice Hall, Salkind. Is stated in declarative form Posits a relationship between variables Reflects theory or literature Is brief and to the point Is testable © 2011 Pearson Prentice Hall, Salkind. © 2011 Pearson Prentice Hall, Salkind. The SAMPLE is a representative portion of a POPULATION The POPULATION is the entire group of interest Results from the SAMPLE should generalize to the POPULATION © 2011 Pearson Prentice Hall, Salkind. © 2011 Pearson Prentice Hall, Salkind. Observed differences (PROBABLY) result from the treatment and not from chance Why? ◦ Influences other than the treatment Significance level = risk associated with not being 100% certain that null hypothesis is incorrect © 2011 Pearson Prentice Hall, Salkind. Describe the research process from formulating questions to seeking and finding solutions? Describe the difference between dependent and independent variables? Identify other types of variables that may interfere with the research process? Define a hypothesis and describe how it works? Discuss the value of the null hypothesis? © 2011 Pearson Prentice Hall, Salkind. Describe the differences between a null hypothesis and a research hypothesis? List the characteristics of a good hypothesis? Explain the difference between a sample and the population? Define statistical significance and explain its importance? © 2011 Pearson Prentice Hall, Salkind.