Mean and standard deviation of sample means
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Lucille has a collection of more than 500 songs on her phone that have a mean duration of 215 seconds and a
standard deviation of 35 seconds. Suppose that every week she makes a playlist by taking an SRS of 49 of these
songs, and we calculate the sample mean duration Ä of the songs in each sample.
Calculate the mean and standard deviation of the sampling distribution of 2.
seconds
seconds
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Suppose that 3% of all athletes are using the endurance-enhancing hormone epo (you should be able to simply compute the percentage of all athletes that are not using epo). for our purposes, a “positive” test result is one that indicates presence of epo in an athlete’s bloodstream. the probability of a positive result, given the presence of epo is .99. the probability of a negative result, when epo is not present, is .90. what is the probability that a randomly selected athlete tests positive for epo? 0.0297