Week #13 & 14 Assignment 1. A company that produces bread is concerned about the distribution of the amount of sodium in its bread. The company takes a simple random sample of 100 slices of bread and computes the sample mean to be 103 milligrams of sodium per slice. Assume that the population standard deviation is 10 milligrams. a) Construct a 95% confidence interval estimate for the mean sodium level. b) Construct a 99% confidence interval estimate for the mean sodium level. 2. Fill in the blanks with on of the following: increases, decreases, or stays the same where E =0 . a) As the sample size (n) increases, the margin of error (E) b) As the confidence level (C) increases, the margin of error (E) c) As the standard deviation (0) increases, the margin of error (E)3. The teachers union is concerned about the amount of time teachers spend each week doing schoolwork at home. A simple random sample of 56 teachers had a mean of 8.0 hours per week working at home after school. Assume that the population standard deviation is 1.5 hours per week. a) Construct a 95% condence interval estimate for the mean number of hours per week a teacher spends working at home. b) Does the condence interval support that teachers work at home after school more than 10 hours a week? Why or why not?I 4. A survey of 85 randomly selected homeowners finds that they spend a mean of $67 per month on internet. Assume that the population standard deviation is $14 per month. a) Construct and interpret a 99% confidence interval estimate for the mean amount of money spent per month on internet by all homeowners. b) Does the confidence interval support that internet costs more than $60 per month? Why or why not? 5. The actual time it takes to cook a ten-pound turkey is a normally distributed. Suppose that a random sample of 20 ten pound turkeys is taken with a sample mean of 2.9 hours and a sample standard deviation of 0.24 hours. Calculate a 95% confidence interval for the average cooking time of a ten pound turkey.6. A recent Gallop poll showed Trump's approval rating 40% with a margin or error of 3%. a) Find the confidence interval. c) Does the confidence interval support that more than 50% of Americans approve of Trump? Why or why not? 7. A recent Gallop poll showed that 672 of 1019 adults nationwide think that marijuana should be legalized. a) Find the margin of error that corresponds to a 95% confidence interval. c) Find the 95% confidence interval estimate of the proportion of adults nationwide who think marijuana should be legalized.8. In a recent survey of 1002 people, 701 said that they voted in a recent presidential election. Voting records show that 61% of eligible voters actually did vote. W a) Find the 95% confidence interval estimate of the proportion of people who say that they voted. b) Are the survey results consistent with the actual voter turnout of 61%? Why or why not? c) How would the confidence interval change if we increased the confidence level to 99%? Find the 99% confidence interval estimate to support your
