(TCO 7) A drug manufacturer wants to estimate the percentage of patients who experience cotton mouth when taking their heart medication.

(TCO 7) A drug manufacturer wants to estimate the percentage of patients who experience cotton mouth when taking their heart medication. A survey of 450 patients who took their drug found that 55 experienced cotton mouth. (a) Find a 98% confidence interval for the true proportion of patients who experienced cotton mouth. Show your calculations and/or explain the process used to obtain the interval. (b) Interpret this confidence interval and write a sentence that explains it.(TCO 8) An engineering firm is evaluating their back charges, and from this they claim that their average back charge is $1800. They randomly select 42 customers, and calculate the sample mean back charge to be $2010. If the standard deviation of back charges is $650, and alpha = 0.05, test the claim of the engineering firm. Perform an appropriate hypothesis test, showing the necessary calculations and/or explaining the process used to obtain the results. (TCO 7) A marketing firm wants to estimate the average amount spent by patients at the hospital pharmacy. For a sample of 65 randomly selected patients, the mean amount spent was $93.50 and the standard deviation was $13.25. (a) Find a 95% confidence interval for the mean amount spent by patients at the pharmacy. Show your calculations and/or explain the process used to obtain the interval. (b) Interpret this confidence interval and write a sentence that explains it.