An experimenter tests the hypothesis that physical exercise improves mood. subjects in the experimental group participate on monday and tuesday and those in the control group on wednesday and thursday. what is the extraneous (confounding) variable?
a. the exercise
b. the day of the week
c. the hypothesis
d. the mood (degree of happiness)

An artist entered into a written agreement to sell a patron a partially finished painting once it was complete. the patron later learned that the artist planned to sell the painting to a third party who offered to pay the artist more than the contract price. the patron filed suit to compel the artist to sell the painting to her in accord with the terms of their agreement, while the artist denied that the painting the artist planned to sell to the third party was the subject of the agreement with the patron. at trial, the patron did not introduce the written agreement or explain its absence. rather, the patron sought to testify that, when she signed the agreement, the artist had pointed to the painting in question and stated that it was the patron’s painting. the artist’s attorney objected to the testimony that the artist identified the painting as belonging to the patron. how should the court rule? asustain the objection, because the artist’s statement was hearsay. bsustain the objection, because the patron failed to produce the written agreement or explain its absence. coverrule the objection, because the statement is not hearsay. doverrule the objection, because the statement was relevant.

One of the great societal changes brought about by industrialization in europe was a. slavery. b. urbanization. c. ruralization. d. democracy.

Give an example of a situation in which an individual's pursuit of economic self-interest may not benefit but instead harm the rest of society