Brewed decaffeinated coffee contains some caffeine. VWe want to estimate the amount of caffeine in 8 ounce cups of decaf coffee at local fast food restaurants. Assume that the standard deviation in...

Extracted text: Brewed decaffeinated coffee contains some caffeine. VWe want to estimate the amount of caffeine in 8 ounce cups of decaf coffee at local fast food restaurants. Assume that the standard deviation in the amount of caffeine in 8 ounces of decaf coffee is known to be 2 mg. We took a sample of 256 eight-ounce cups of coffee from fast food restaurants on Robert Street in West St. Paul. The sample mean amount of caffeine turned out to be 8 mg. Construct a 90% confidence interval estimate for the true mean amount of caffeine in eight-ounce cups of decaf coffee, using the information described above. Type the formula for your confidence interval into the text box first'and then type a second version where you fill in all of the numbers in your formula. You don't have to calculate the final numeric result.