Term | Definition |
Complex hypothesis | A statement explaining and/or predicting relationships between two or more independent and dependent variables |
Dependent variable | A variable that is observed for changes or to assess the possible effect of a treatment or manipulation; may be the effect or outcome of an experimental procedure; also referred to as a criterion or outcome variable. Usually symbolized by the letter Y |
Directional hypothesis | A hypothesis that makes a specific prediction about the direction of the relationship between two variables |
Extraneous variable | A variable that is not controlled for in a study, threatening the internal validity of the study. Can affect your outcome without you wanting it to |
Hypothesis | A statement about the relationship between the variables that are being investigated |
Independent variable | A variable that is manipulated and controlled by the researcher; also called a predictor variable. Usually symbolized by the letter X. This is what is changed! Affects the dependent variable |
Nondirectional hypothesis | A hypothesis that does not stipulate in advance the direction and nature of the relationship between two variables |
Null hypothesis (H) | A hypothesis stating that no relationship or difference exists between two variables. Also called statistical hypothesis |
Research hypothesis (H1 or Ha) | A hypothesis stating a relationship or difference between two variables. Also called an alternative, declarative, or scientific hypothesis |
Research Questions | A concise, interrogative statement written in the present tense including one or more variables |
Simple hypothesis | A statement explaining and/or predicting a relationship between one independent and one dependent variable |
Variable | A measurable characteristic that varies among the subjects being studied |
Operational Definition | Further describes the variables, to make it more clear. Ex: When you say "lung function", what exactly are you talking about?
Expansion? Etc. This is so everybody knows what the terms mean |
Purpose Statement | Explains why the study is being done (the reason, the purpose) |