QUESTION
1: Volunteers who had developed a cold within the previous 24 hours were randomized to take either zinc or placebo lozenges every 2 to 3 hours until their cold symptoms were gone.Twenty-fiveparticipants took zinc lozenges, and21participants took placebo lozenges. The mean overall duration of symptoms for the zinc lozenge group was3.1days, and the standard deviation of overall duration of symptoms was1.5days. For the placebo group, the mean overall duration of symptoms was5.3days, and the standard deviation was1.9days. Use the pooled procedure to compute a 95% confidence interval for the difference in mean days of symptoms for the zinc and placebo treatments. (Round all answers to the nearest hundredth.)___to___days2: Consider this quote: “In a recent survey, 80 out of 100 consumers reported that they preferred plastic bags instead of paper bags for their groceries. If there is no difference in the proportions who prefer each type in the population, the chance of such extreme results in a sample of this size is about .03. Because .03 is less than .05, we can conclude that there is a statistically significant difference in preference.” Give a numerical value for the null value
ANSWER:
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