Module 6 – Variables Hypothesis Relationships

what is a concept in regards to epi

Mental image comprising observations, feelings, or ideas

• ideas: empathy, racism, sexism, femininity,

• events: childbirth, onset of symptoms, experience of violence

• behavior: aggressive, passive, violent, empathetic,

• person: healthy, unhealthy, intelligent, hardworking

conceptualization

the process of defining meaning of the terms we use

• the progression from an abstract concept to a specific measurement for a research study

• concept → dimension → indicator → variable

when ideas or observations are operationalized into pieces of data that contain measured values we get

variables

Independent variable (IV)

• Considered the “cause” or input

  • aka exposures, intervention

  • its status/value is “independent” of the outcome (temporality)

  • hypothesized effect on the dependent variable

  • at least one IV in a study, usually more

  • manipulated (assigned) in some studies

Measured IV

• observational studies

• reasearcher does not control the IV

Manipulated/assigned IV

• experimental studies

• researcher does control the IV

Dependent Variable (DV)

• varies with the change in the independent variable

• its status/value “depends” on the status/value of the IV (assuming there is a relationship between the two)

• considered the “effect” or outcome

• is never manipulated or assigned; always measured/reordered

  • aka response variable

Hypotheses

• statements that predict the nature and extent of relationships between variables

  • tentative statements (may be right or wrong)

• Based on your research question or research goals

  • informed by previous literature, preliminary studies, or theory

• Used in quantitative studies

• Specific and measurable (refer to variables)

• Stated in such a way that they can be accepted or rejected

Alternative Hypothesis

What the researcher thinks will happen

• written H_a

Null Hypothesis

“No difference” hypothesis

• written H0

• what you are actually testing with your data

  • rejecting the null hypothesis means there is a difference

  • failing to reject the null hypothesis means there is NO difference between the groups (or no relationship between the variables)

If the cause occurs before the effect

temporality

positive (linear) relationship

as one variable increases so does the other

Negative (linear) relationship

as one variable increases the other variable decreases

Confounding

• third variable that distorts your results

• related to IV and DV

• not in a causal pathway