STAT 100 Study Guide - Final Guide: Simple Random Sample, Mutual Exclusivity, Null Hypothesis
Document Summary
Good luck: [5 pts] a researcher is interested in whether more sleep boosts the immune system. So she calls a random sample of 400 people and asks them how many colds they"ve gotten in the past year, and also how many hours of sleep they get on average per night. She calculates that the people who slept 7 or more hours a night had 2. 1 colds on average last year, while the people who slept less than 7 hours a night had 3. 4 colds on average last year. She then concludes that there"s good evidence that sleep lets the immune system better deal with viruses. Solution: 25, because the area to the right of 25 looks like about one tenth of the total area under the curve. 2: say we"ve collected data on the length of people"s thumbs and pinkies, and have gotten the following results: Thumb average = 3 in, thumb sd = 0. 25 in.
