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Chapter 7 homework James studies the amount of time people spend watching movie trailers online. In the general population, this amount of time (in hours) is normally distributed with pp: = 0.75 and o = 0.2. a) What is the probability of randomly selecting a sample of 81 people who watch, on average, at least 0.81 hours of movie trailers online? b) What sample means separate the middle 95% of the distribution, if n=64