Question

Spiders regularly engage in spider foreplay that does not culminate in mating. Male spiders mature faster than female spiders and often practice the mating routine on not-yet-mature females. Since male spiders run the risk of getting eaten by female spiders, biologists wondered why spiders engage in this behavior. In one study, some spiders were allowed to participate in these near-matings, while other maturing spiders were isolated. When the spiders were fully mature, the scientists observed real matings. They discovered that if either partner had participated at least once in mock sex, the pair reached the point of real mating significantly faster than inexperienced spiders did. (Mating faster is, apparently, a real advantage in the spider world.) Describe the variables, indicate whether each variable is quantitative or categorical, and indicate the explanatory and response variables.

Short answer

The variables are 'Participation in near-matings' and 'Speed of reaching real mating upon maturity'. 'Participation in near-matings' is a categorical variable, while 'Speed of reaching real mating upon maturity' is a quantitative variable. The explanatory variable is 'Participation in near-matings', and the response variable is 'Speed of reaching real mating upon maturity'.

Step-by-step solution

Identifying the Variables

Read through the exercise carefully and note all the mentions of different conditions or aspects being studied. In this exercise, the variables are: 1) Participation in near-matings, 2) Speed of reaching real mating upon maturity.

Classifying the Variables as Quantitative or Categorical

A variable is quantitative if it represents a measurable quantity, whilst it is categorical if it represents a quality or characteristic. Participation in near-matings is a categorical variable since the spiders either participated (yes) or did not participate (no). Speed of reaching real mating upon maturity is a quantitative variable as it can be measured.

Identifying the Explanatory and Response Variables

Explanatory variables are those that may cause or explain changes in the response variable. In this exercise, the explanatory variable is Participation in near-matings and the response variable is Speed of reaching real mating upon maturity. This is because the exercise indicates that participation in near-matings may affect how quickly spiders reach maturity.