A dairy scientist is testing a new feed additive. She chooses 13 cows at random from a large population of cows. She randomly assigns nold = 8 to get the old diet, and nnew = 5 to get the new diet including the additive. The cows are housed in 13 separated pens and each gets separate feed, with or without additive as appropriate. After two weeks, she picks a day and milks each cow using standard procedures and records the milk produced in pounds. The data are below:Old Diet: 43, 51, 44, 47, 38, 46, 40, 35New Diet: 47, 75, 85, 100, 58Let µnew and µold be the population mean milk productions for the new and old diets, respectively. She wishes to test: H0 : µnew vs µold = 0 vs. HA : µnew vs µold 6= 0, using α = 0.05.(a) Are the two populations paired or independent?

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general 10 months ago 3829

The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minutes. We want to see if we can find significant evidence to prove that the mean waiting time of all customers is significantly more than 3 minutes. The test statistic is 2. What is the p-value? Round your answer to three decimal places.

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general 10 months ago 3258

In 2008 the Pew Research Center interviewed a random sample of 5,566 registered voters and found that 36% were Democrats, 27% Republicans, and 37% Independents. Let’s assume that this was the actual distribution for political party affiliation for all registered voters in 2008. We can use a chi-square goodness-of-fit test to answer which of one the following research questions? a. Is the proportion of Democrats larger than the proportion of Republicans this year? b. Is the percentage of registered voters that are Independent higher now than the 37% reported in 2008? c. Is the distribution of political party affiliation for all registered voters in 2012 the same as stated for 2008?

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general 10 months ago 3341

A newspaper article about an opinion poll says that "53% of Americans approve of the president's overall job performance." The poll is based on online survey interviews with 1,350 adults randomly chosen from a numbered list of one million responses from around the United States, excluding Alaska and Hawaii.Part A: What is the population and sample in this poll? (3 points)Part B: What type of sampling is used? (3 points)Part C: Are there any sources of bias present? Explain. (4 points) (10 points)

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general 10 months ago 1394