A class survey in a large class for firstyear college students asked, "About how many hours do you study during a typical week?" The mean response of the 463 students was ????=13.7 hours. Suppose that we know that the study time follows a Normal distribution with standard deviation ????=7.4 hours in the population of all firstyear students at this university. The 99% confidence interval was found to be approximately 12.814 to 14.586 hours. There were actually 464 responses to the class survey. One student had claimed to study 10,000 hours per week (10,000 is more than the number of hours in a year). We know he's joking, so we left out this value. If we did a calculation without looking at the data, we would get ????=35.2 hours for all 464 students. Using either my Excel spreadsheet, Ti Calcuator or Crunchit, the 96% confidence interval for the population mean? Continue to use ????=7.4 . Group of answer choices a. 12.814 to 14.586 hours. b. 34.32 to 36.09 hours. c. 34.52 to 35.87 hours. d. 34.49 to 35.91 hours