Randomization in an experiment is important because it ensures that the treatments have an effect on the response. the individuals who will be in the study were chosen randomly. the groups of subjects are similar, on average, in all respects before applying the different treatments to the different groups. each individual has a fair chance of being included in the study. each treatment is thought of as a value of the explanatory variable.

Astudent is determining the influence of different types of food on the growth rate of spiders. she feeds one group of spiders two caterpillars twice a week. the other group received similarly-sized beetles twice a week. she records the amount of time required for individuals to reach sexual maturity. her hypothesis is that the spiders feeding on caterpillars will have a faster growth rate because caterpillars have a higher protein content compared to beetles. in this experiment, what is the dependent variable? spiders assigned to different feeding groups. time required to reach sexual maturity number of prey items fed twice a week. growth rates of each group.