Hypotheses part 2

• A directional hypothesis states the nature or direction of a proposed relationship.
• Directional hypotheses are developed from theoretical statements, previous research findings, and clinical experience.
• Terms such as less, more, increase, decrease, positive, negative, greater, and smaller indicate the directions of relationships in hypotheses.
• All causal research hypotheses are directional because the independent variable is predicted to cause a specific change (increase or decrease) in the dependent variable.
• A nondirectional hypothesis, as the definition implies, does not specify the direction of the relationship between and among variables.
• The null hypothesis (H0), also referred to as a statistical hypothesis, is used for statistical testing and interpretation of study results.
• An associative null hypothesis states that there is no relationship between the variables studied.
• Null hypotheses that state no relationships among variables, no difference between study groups, or no effect of an intervention on a study outcome are nondirectional.
• Variables or concepts are ideas, qualities, properties, or characteristics of persons, things, or situations that are studied in research.
• Qualitative research does not refer to concepts as variables, except in the special case of grounded theory research in which the sole central concept revealed at the end of the study through data analysis is sometimes called the core variable.
• Demographic variables are subject or participant characteristics measured during a study and used to describe a sample.
• Demographic variables typically include age, gender, and race/ethnicity.
• For hospital-based studies, additional demographic variables typically include medical diagnosis, acuity, and length of stay.
• In nonhospital settings, educational level, income, and occupation may be included as demographics, especially when provision of services is a study focus.