Data were collected on the amount spent by 64 customers for lunch at a major houston restaurant. these data are contained in the file named houston. based upon past studies the population standard deviation is known with = $9. click on the datafile logo to reference the data. a. at 99% confidence, what is the margin of error? b. develop a 99% confidence interval estimate of the mean amount spent for lunch.
amount
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