The following measurements (in picocuries per liter) were recorded by a set of carbon dioxide detectors installed in a manufacturing facility: 799.2,784.3,803.8,806.8,780.5,794.8 Using these measurements, construct a 95% confidence interval for the mean level of carbon dioxide present in the facility. Assume the population is approximately normal. Step 1 of 4 : Calculate the sample mean for the given sample data. Round your answer to two decimal places.