Here are the tips of 25 randomly selected patrons, measured in percent of total bill. 20.8 18.7 19.9 20.6 21.9 23.4 22.8 24.9 22.2 20.3 24.9 22.3 27.0 20.4 22.2 24.0 21.1 22.1 22.0 22.7 19.1 20.6 22.3 22.0 29.4 The standard deviation of tips is known to be 2.5. a) What is the 94% confidence interval for the mean tip of patrons if the distribution of tips is approximately Normal? b) What is the 98% confidence interval for the mean tip of patrons if the distribution of tips is unknown?