The pew research center estimates that as of january 2014, 89% of 18-29 year olds in the united states use social networking sites. calculate the probability that at least 91% of 500 randomly sampled 18-29 year olds use social networking sites.

College students signed up to be subjects in a psychology experiment. when they arrive, they are told that interviews are running late, and they are left in a waiting room. the experimenters have placed a cell phone in the room and the subjects are told not to answer the phone no matter how many times it rings. some subjects are in the room alone and others are in pairs; these are the treatments being compared. will the subject answer the phone? the students agreed to take part in an unspecified experiment, and the true nature of the experiment is explained to them afterward. does this meet the requirement of informed consent? explain. yes, because they agreed to participate in an experiment yes, because they are not forced to answer the phone no, because they had to wait for the interviews no, because they did not know the nature of the experiment before participating unable to determine whether subjects consented to experiment