Alcohol and heart attacks. Many studies have found that people who drink alcohol in moderation have lower risk of heart attacks than either nondrinkers or heavy drinkers. Does alcohol consumption also improve survival after a heart attack? One study followed 1913 people who were hospitalized after severe heart attacks. In the year before their heart attacks, 47% of these people did not drink, 36% drank moderately, and 17% drank heavily. After four years, fewer of the moderate drinkers had died.
a) Is this an observational study or an experiment? Why? What are the explanatory and response variables?
b) Suggest some lurking variables that may be confounded with the drinking habits of the subjects. The possible confounding makes it difficult to conclude that the drinking habits explain death rates.
(a) This is an observational study since a group of people was monitored over a period of time (with the intention of seeing
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Statistics - Probability..
A golf course in Hawaii has determined that the mean time it takes for a group to complete an 18 hole round of golf is 4 hours 35 minutes or 275 minutes with a standard deviation of 14 minutes. The time distribution is also thought to be approximately normal. On a monthly basis, the head pro at the course randomly selected a sample of 8 groups and monitored the time it takes them to play. Suppose the mean time that was observed for the sample last month was 4 hours 44 minutes (284 minutes). What is the probability of seeing a sample mean this high or higherView Full Posting Details