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 = $7. 20.50 14.63 23.77 29.96 29.49 32.70 9.20 20.89 28.87 15.78 18. 16 12. 16 11.22 16.43 17.66 9.59 18.89 19.88 23.11 20.11 20.34 20.08 30.36 21.79 21.18 19.22 34.13 27.49 36.55 18.37 32.27 12.63 25.53 27.71 33.81 21.79 19.16 26.35 20.01 26.85 13.63 17.22 13.17 20.12 22.11 22.47 20.36 35.47 11.85 17.88 6.83 30.99 14.62 18.38 26.85 25.10 27.55 25.87 14.37 15.61 26.46 24.24 16.66 20.85 (a) At 99% confidence, what is the margin of error in dollars? (Round your answer to the nearest cent. ) $ (b) Develop a 99% confidence interval estimate of the mean amount spent for lunch in dollars. (Round your answers to the nearest cent. ) $ to $