The Research Process: Coming to Terms 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. 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. From Problem to Solution All About Variables Other Important Types of Variables Hypotheses Samples and Populations The Concept of Significance Increasing our understanding of how and why we behave the way we do!! 1
From Problem to Solution Noting an interesting question Stating the question in such a way that it can be answered The Language of Research 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 The outcomes of a research study Depend on the experimental treatment Treatments or conditions under control of the researcher Levels at least two different values of the independent variable must be present 2
Independent variable is not confounded Levels do not vary systematically with other variables Dependent variable is sensitive to changes in the independent variable 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 Type of Variable Dependent Independent Control Extraneous Moderator Definition A variable that is measured to see whether the treatment or manipulation of the independent variable had an effect A variable that is manipulated to examine its impact on a dependent variable A variable that is related to the dependent variable, the influence of which needs to be removed A variable that is related to the dependent variable or independent variable that is not part of the experiment A variable that is related to the dependent variable or independent variable and has an impact on the dependent variable Other Terms You Might See Outcome variable Results variable Criterion variable Treatment Factor Predictor variable Restricting variable Threatening variable Interacting variable Reflects the general problem under study Restates the general problem in a form that is precise enough to allow testing 3
States that there is no relationship between the independent and dependent variables under study H o : 1 = 2 H o : Null hypothesis 1 : Theoretical average of population 1 2 : Theoretical average of population 2 A starting point for analysis Accepted as true absent other information Assumes that chance caused any observed differences Provides a benchmark for comparison A statement of inequality A relationship exists between the independent and dependent variables H 1 : X 1 X 2 H 1 : Research hypothesis X 1 : Theoretical average of population 1 : Theoretical average of population 2 X 2 Nondirectional Research Hypothesis Groups are different, but direction is not specified H 1 : X 1 X 2 Directional Research Hypothesis Groups are different, and direction is specified H 1 : > X 1 X 2 H 1 : < X 1 X 2 Directly tested during research process To compare against null hypothesis Null Equality between variables Refers to population Indirectly tested Stated using Greek symbols () Implied Research Inequality between variables Refers to sample Directly tested Stated using Roman symbols ( ) X Explicit 4
Is stated in declarative form Posits a relationship between variables Reflects theory or literature Is brief and to the point Is testable 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 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 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? 5
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? 6