The stimulus-response model describes a statistical unit as making a quantitative response to a quantitative stimulus administered by the researcher. The object of this kind of research is to establish a mathematical function that describes the relation <math>f</math> between the stimulus <math>x</math> amd the response <math>y</math>:
<math>y = f(x)</math>
The most common form assumed for such functions is linear, thus we expect to see a relationship like
... there are 19,701 people, 6,700 households, and 5,011 families residing in the town. The population density is 1,549.2/km² (4,010.1/mi²). There are 6,949 housing ...