Confidence Intervals for Proportions 1. In 2001 the Gallop organization conducted a poll to determine the condence that Americans have in the food that they purchase in grocery stores. Gallop conducted telephone interviews with was randomly selected US adults who answered the question, \"Do you feel condent or not confident that the food available at most grocery stores is safe to eat?\" The results are summarized below: m sass _ The Gallop News Service goes on to say that "For results based on this sample, one can say with 95% confidence that the maximum error attributable to sampling and other random effects is plus or minus 3 percentage points.\" a. Find a 95% condence interval for the proportion of all US adults {in July 2001] who feel confident that the food available in most grocery stores is safe to eat. b. Compare the margin of error in part {a} with the error reported by Gallop. 2. A survey of residents in a certain county is undertaken to investigate the proportion of adults who have two or more credit cards. In a random sample of 35 adult residents, 25 indicated they had at least two credit cards. Form a 99% condence interval for the percentage of all residents in the county that have two or more credit cards. 3. In October 2010, the Gallop Poll asked 510 randomly sampled adults the question, \"Generally speaking, do you believe the death penalty is applied fairly or unfairly in this country today?\" [if these, 53% answered \"Fairly," 36% answered \"Unfairly,\" and 7% said they didn't know. From this survey what can we conclude about the opinions of all adults