tips <-
structure(list(week = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L), day = structure(c(2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = c("Friday", "Tuesday"
), class = "factor"), n_peop = c(0.67000000000000004, 1.3300000000000001, 
5.3300000000000001, 2.6699999999999999, 1.3300000000000001, 2, 
1.3300000000000001, 2.6699999999999999, 2, 1.3300000000000001, 
1.3300000000000001, 1.3300000000000001, 1.3300000000000001, 7.3300000000000001, 
4.6699999999999999, 1.3300000000000001, 1.3300000000000001, 2.6699999999999999, 
1.3300000000000001, 1.3300000000000001, 6, 6, 3.3300000000000001, 
1.3300000000000001, 0.67000000000000004, 2.6699999999999999, 
0.67000000000000004, 5.3300000000000001, 1.3300000000000001, 
4, 4, 2.6699999999999999, 4.6699999999999999, 8.6699999999999999, 
1.3300000000000001, 2.6699999999999999, 5.3300000000000001, 0.67000000000000004, 
0.67000000000000004, 1.3300000000000001, 4, 1.3300000000000001, 
2, 2, 2, 0.67000000000000004, 2, 2, 1.3300000000000001, 1.3300000000000001, 
2, 6.6699999999999999, 1.3300000000000001, 2, 4.6699999999999999, 
2, 2.6699999999999999, 2.6699999999999999, 8, 9.3300000000000001, 
1.3300000000000001, 2.6699999999999999, 1.3300000000000001, 2.6699999999999999, 
1.3300000000000001, 2, 1.3300000000000001, 0.67000000000000004, 
9.3300000000000001, 8, 6.6699999999999999, 2, 0.67000000000000004, 
2, 0.67000000000000004, 4.6699999999999999, 1.3300000000000001, 
1.3300000000000001, 0.67000000000000004, 2, 2.6699999999999999, 
2.6699999999999999, 2, 2, 0.67000000000000004, 4, 2, 0.67000000000000004, 
0.67000000000000004, 4, 1.3300000000000001, 4, 1.3300000000000001, 
1.3300000000000001, 8.6699999999999999), bill = c(17.989999999999998, 
26.050000000000001, 79.489999999999995, 32.689999999999998, 29.969999999999999, 
23.91, 18.18, 41.229999999999997, 25.190000000000001, 19.219999999999999, 
20.600000000000001, 30.149999999999999, 31.030000000000001, 124.44, 
69.400000000000006, 23.449999999999999, 19.75, 39.880000000000003, 
21.190000000000001, 17.829999999999998, 91.430000000000007, 78.180000000000007, 
53.039999999999999, 26.75, 15.23, 28.050000000000001, 10.99, 
71.469999999999999, 24.710000000000001, 66.480000000000004, 53.390000000000001, 
38.880000000000003, 60.170000000000002, 124.90000000000001, 24.82, 
35.710000000000001, 75.120000000000005, 8.3100000000000005, 14.57, 
20.07, 64.25, 22.379999999999999, 30.210000000000001, 23.27, 
22.359999999999999, 18.649999999999999, 32.329999999999998, 34.350000000000001, 
23.780000000000001, 19.68, 20.82, 96.109999999999999, 15.140000000000001, 
36.770000000000003, 59.969999999999999, 27.329999999999998, 30.989999999999998, 
35.119999999999997, 117.15000000000001, 144.18000000000001, 21.370000000000001, 
32.450000000000003, 25.050000000000001, 42.509999999999998, 10.91, 
33.719999999999999, 25.210000000000001, 19.079999999999998, 141.75999999999999, 
93.370000000000005, 101.26000000000001, 42.810000000000002, 4.9800000000000004, 
28.170000000000002, 5.5499999999999998, 60.469999999999999, 24.670000000000002, 
17.77, 13.67, 23.25, 31.379999999999999, 42.549999999999997, 
39.130000000000003, 38.770000000000003, 10, 72.840000000000003, 
29.07, 14.83, 18.309999999999999, 64.930000000000007, 25.039999999999999, 
76.269999999999996, 24.210000000000001, 34.049999999999997, 115.39
), tip = c(2, 4, 14.308199999999999, 5.5, 6, 7.5, 3.0600000000000001, 
8.5, 8.5, 3, 5, 3.5, 3, 22.3992, 18, 8.5, 2.5, 7.5, 5, 2.25, 
16.4574, 14.0724, 7.5700000000000003, 0, 2.8100000000000001, 
3, 2, 12.864599999999999, 3, 16, 7, 2.8999999999999999, 7, 22.481999999999999, 
6, 6, 13.521599999999999, 1.5, 7, 3, 5.5, 3.25, 6, 2, 3.5, 6, 
3.5, 7.3200000000000003, 9.5, 3, 3.5, 17.299800000000001, 2.5, 
4, 9, 4, 3.25, 6, 21.087, 25.952400000000001, 6, 5.5, 4, 6.5, 
3, 7.75, 6, 4, 25.5168, 16.8066, 18.226800000000001, 5, 0.5, 
7.5, 0.75, 15, 6, 0.75, 3.5, 7, 8, 6, 6, 4, 3.5, 11.5, 7, 1.5, 
1, 7, 6, 13, 3.75, 8.5, 20.770199999999999)), row.names = c(NA, 
-95L), class = c("tbl_df", "tbl", "data.frame"))