Q.A researcher is studying the relationship between speed of cycling and the presence of people. Formulate a relevant hypothesis and identify the independent and dependent variables.

A variable is any stimulus or event that can take on different values, or vary, and that can be measured; an object itself is never a variable, but its attributes are. In any experiment, psychologists are chiefly concerned with two kinds of variable. The independent variable is the one the researcher deliberately manipulates, alters, or varies in strength or intensity; it is chosen because the researcher wants to observe the effect that changing it produces. The dependent variable is the variable on which that effect is actually observed and measured; it represents the very phenomenon or behaviour the researcher is trying to explain, and it is expected to change as a consequence of changes in the independent variable. Put simply, in any experimental situation the independent variable functions as the cause, and the dependent variable functions as the effect; the two are mutually interdependent, in that neither one can really be defined or understood without reference to the other. Correctly telling the two apart is a key first step in designing or interpreting any experiment or hypothesis: the general rule is to ask which factor the researcher is deliberately changing or …