Find the multiple R for predicting y from the X1 and X2 variables

"Natural selection" is a process by which

A) favorable traits become increasingly common in a population of interbreeding individuals, while traits that are unfavorable become less common. B) animal breeders select animals in each generation that have the most "natural" traits to breed the next generation. C) favorable traits become increasingly common in a population over the course of a single generation. D) genetic mutations lead to random changes within a population of organisms.

Cohen proposed effect-size conventions based on the effects observed in psychology research in general because

A) experimenters need to assess whether the obtained effect size will allow them to reject the null hypothesis. B) determining how large an effect can be expected in a given experiment is difficult. C) they follow from the original scales he developed. D) they are more accurate than calculating a minimum meaningful difference.