Data were collected on the amount spent by 64 customers for lunch at a major Houston restaurant. These data are contained in the file Houston. Based upon past studies the population standard deviation is known with o = $10. Click on the datafile logo to reference the data. DATA file Round your answers to two decimal places. Use the critical value with three decimal places. a. At 99% confidence, what is the margin of error? 3.22 b. Develop a 99% confidence interval estimate of the mean amount spent for lunch. 67.22 to $ -3.22