Which scientific investigation does not include dependent and independent variables?

 One is called the dependent variable and the other the independent variable. The independent variable is the variable the experimenter changes or controls and is assumed to have a direct effect on the dependent variable. Two examples of common independent variables are gender and educational level.

Explanation:

An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable. A dependent variable is the variable being tested and measured in a scientific experiment.

also the Independent variable – the variable that is altered during a scientific experiment. Dependent variable – the variable being tested or measured during a scientific experiment. Controlled variable – a variable that is kept the same during a scientific experiment.

The dependent variable is the variable that is being measured or tested in an experiment. For example, in a study looking at how tutoring impacts test scores, the dependent variable would be the participants' test scores, since that is what is being measured.