Select all of the true statements about a placebo-controlled randomized comparative experiment. A. The placebo control group is designed to control for bias on the part of the researcher. B. The experimental design of a placebo-controlled randomized comparative experiment involves dividing subjects into subgroups based on similar characteristics, followed by randomly assigning treatments to subjects within each subgroup. C. Experimental subjects are assigned to the treatment and control groups randomly, such that chance rather than conscious or unconscious decision determines which units end up receiving the treatment of interest and which receive the placebo. D. A placebo is an inactive substance that appears to be the same as the experimental treatment. The placebo effect is the phenomenon in which subjects report improvement in their condition after taking a placebo. E. A placebo control group receives the standard treatment or a diluted treatment. A placebo effect occurs when the placebo yields a positive response from subjects taking it.

Design an er diagram for keeping track of information about votes taken in the u.s. house of representatives during the current two-year congressional session. the database needs to keep track of each u.s. state's name (e.g., texas', new york', california') and include the region of the state (whose domain is {northeast', midwest', southeast', southwest', west'}). each congress person in the house of representatives is described by his or her name, plus the district represented, the start date when the congressperson was first elected, and the political party to which he or she belongs (whose domain is {republican', democrat', 'independent', other'}). the database keeps track of each bill (i.e., proposed law), including the bill name, the date of vote on the bill, whether the bill passed or failed (whose domain is {yes', no'}), and the sponsor (the congressperson(s) who sponsored - that is, proposed - the bill). the database also keeps track of how each congressperson voted on each bill (domain of vote attribute is {yes', no', abstain', absent'}). additional information: