1	11115722	MEX	F	801.66	GRPB	5
2	11122053	USA	M	599.41	GRPB	2
3	11128688	USA	F	1610.13	GRPA	6
4	11130578	USA	F	1599.46	GRPA	3
5	11130759	ESP	M	1837.40	GRPB	3
6	11131070	USA	M	294.15	GRPB	4
7	11131381	GBR	F	1927.14	GRPB	4
8	11131664	TUR	M	3094.14	GRPB	7
9	11132813	USA	M	608.66	GRPA	2
10	11134390	DEU	F	368.15	GRPB	2
11	11136982	USA	F	3303.81	GRPA	5
12	11140660	TUR	M	3519.06	GRPB	10
13	11143138	BRA	M	2717.97	GRPB	8
14	11146038	MEX	M	1618.53	GRPA	5
15	11148089	DEU	F	584.85	GRPA	4
16	11148343	BRA	M	406.57	GRPB	1
17	11149066	DEU	M	1020.62	GRPB	4
18	11149952	ESP	M	63.24	GRPA	2
19	11154067	MEX	F	612.76	GRPA	4
20	11154169	USA	M	2147.28	GRPB	5
21	11154371	FRA	F	2011.31	GRPB	5
22	11156956	USA	F	2241.49	GRPB	5
23	11158482	FRA	F	1690.42	GRPB	4
24	11159147	AUS	F	3870.19	GRPB	6
25	11159247	DEU	M	0.00	GRPA	9
26	11161660	DEU	M	1307.06	GRPB	3
27	11161698	DEU	F	1031.45	GRPB	3
28	11166921	CAN	F	1487.15	GRPA	4
29	11168706	DEU	F	906.16	GRPA	5
30	11169359	CAN	F	488.31	GRPB	4
31	11172690	USA	F	1733.54	GRPB	3
32	11172970	BRA	M	2449.70	GRPB	3
33	11174279	DEU	F	0.00	GRPA	9
34	11174686	MEX	F	3996.56	GRPA	7
35	11175748	USA	F	308.18	GRPB	8
36	11176494	FRA	M	0.00	GRPA	2
37	11177332	BRA	M	2316.72	GRPB	6
38	11179295	BRA	M	482.76	GRPB	2
39	11183316	BRA	M	1306.36	GRPA	5
40	11183929	USA	M	465.86	GRPA	2
41	11183968	ESP	M	298.72	GRPA	4
42	11185760	USA	F	1086.54	GRPB	3
43	11188872	TUR	M	0.00	GRPA	10
44	11189834	GBR	F	307.58	GRPB	1
45	11190107	BRA	M	562.59	GRPB	5
46	11193748	ESP	M	88.00	GRPA	1
47	11198393	DEU	M	127.45	GRPA	1
48	11199766	ESP	F	149.72	GRPA	1
49	11200044	FRA	F	895.13	GRPA	5
50	11205334	USA	M	6102.80	GRPA	9
51	11207802	TUR	F	229.34	GRPA	3
52	11209959	FRA	F	573.11	GRPA	3
53	11212140	USA	F	3403.26	GRPB	7
54	11213287	USA	F	783.02	GRPA	7
55	11214941	CAN	M	2120.36	GRPA	5
56	11215412	BRA	F	426.89	GRPB	3
57	11217999	USA	F	249.58	GRPA	4
58	11219054	USA	M	1843.95	GRPA	3
59	11219057	USA	M	0.00	GRPB	6
60	11220745	FRA	M	1557.50	GRPB	5
61	11222138	BRA	F	2367.55	GRPB	4
62	11222433	BRA	F	836.13	GRPA	8
63	11224003	USA	F	763.79	GRPA	2
64	11224831	BRA	M	966.82	GRPB	3
65	11225482	TUR	M	4207.76	GRPA	8
66	11227217	USA	M	1235.29	GRPB	3
67	11227363	USA	F	3694.87	GRPB	6
68	11229291	MEX	M	1482.34	GRPB	2
69	11229421	BRA	F	1209.66	GRPA	2
70	11232570	GBR	F	3570.95	GRPA	11
71	11235763	MEX	F	345.72	GRPA	1
72	11237686	BRA	M	880.86	GRPA	2
73	11239814	USA	M	1856.95	GRPA	3
74	11241555	DEU	F	70.41	GRPA	2
75	11243475	AUS	M	458.50	GRPA	1
76	11243819	BRA	F	1018.38	GRPA	5
77	11247467	USA	F	3340.66	GRPA	12
78	11248067	CAN	M	2960.81	GRPA	9
79	11249369	BRA	M	590.74	GRPB	3
80	11252669	BRA	F	229.52	GRPA	2
81	11252904	GBR	F	968.58	GRPA	4
82	11253355	MEX	M	619.10	GRPA	2
83	11254419	TUR	F	1230.42	GRPB	3
84	11258319	DEU	M	2042.30	GRPB	3
85	11260969	DEU	M	170.32	GRPA	2
86	11262533	BRA	F	1273.09	GRPB	4
87	11264431	BRA	F	737.99	GRPA	1
88	11267183	MEX	M	2692.44	GRPA	6
89	11267642	BRA	M	1068.82	GRPB	3
90	11268448	USA	M	654.26	GRPA	4
91	11271187	BRA	M	141.20	GRPB	1
92	11271578	BRA	F	1720.33	GRPB	4
93	11275532	MEX	F	1564.43	GRPA	7
94	11277649	USA	F	1525.11	GRPA	4
95	11281238	USA	M	929.75	GRPA	5
96	11284044	GBR	F	615.25	GRPB	4
97	11285665	USA	M	1191.63	GRPA	3
98	11286261	BRA	M	622.63	GRPB	5
99	11286996	MEX	M	0.00	GRPB	11
100	11288502	BRA	M	3094.68	GRPB	8
101	11292588	DEU	F	1312.22	GRPA	4
102	11295764	USA	M	2258.15	GRPB	10
103	11296374	DEU	M	937.73	GRPB	4
104	11296542	USA	M	1719.21	GRPA	3
105	11297160	MEX	M	1393.81	GRPB	4
106	11301932	ESP	F	3358.15	GRPA	6
107	11301943	USA	F	1238.05	GRPB	3
108	11308086	TUR	M	2469.13	GRPA	7
109	11308139	BRA	F	1414.73	GRPA	4
110	11310618	MEX	M	0.00	GRPA	13
111	11311734	DEU	F	2387.56	GRPA	6
112	11316042	USA	F	1145.70	GRPB	4
113	11316941	ESP	M	166.32	GRPA	1
114	11317427	USA	M	2847.93	GRPA	4
115	11317921	USA	F	5640.64	GRPB	13
116	11318017	BRA	F	2358.09	GRPB	19
117	11322820	TUR	M	0.00	GRPB	9
118	11324159	BRA	F	3725.71	GRPB	5
119	11324591	BRA	F	826.79	GRPA	1
120	11327441	USA	M	1928.31	GRPB	6
121	11327700	AUS	M	4822.77	GRPB	11
122	11328768	MEX	M	437.10	GRPB	2
123	11330951	ESP	F	476.13	GRPA	3
124	11332595	USA	M	812.90	GRPB	6
125	11337910	USA	F	2032.10	GRPA	8
126	11341621	BRA	M	1179.37	GRPA	2
127	11343422	USA	M	252.07	GRPA	2
128	11345178	GBR	F	363.03	GRPB	4
129	11348460	DEU	F	118.87	GRPA	2
130	11348704	USA	M	2871.83	GRPA	6
131	11349003	DEU	M	288.15	GRPA	2
132	11353954	MEX	F	672.63	GRPA	1
133	11354378	USA	M	1039.07	GRPB	3
134	11355479	CAN	F	3616.45	GRPA	5
135	11356333	GBR	M	496.92	GRPA	1
136	11357019	USA	M	2860.42	GRPB	6
137	11358621	TUR	M	1995.84	GRPB	4
138	11359110	FRA	M	2635.74	GRPA	5
139	11361120	ESP	F	4549.18	GRPB	9
140	11366885	FRA	M	213.85	GRPB	1
141	11367989	BRA	M	373.86	GRPB	3
142	11371388	USA	M	2083.08	GRPB	6
143	11372201	USA	M	125.78	GRPB	3
144	11374362	FRA	M	998.55	GRPB	6
145	11375211	USA	M	3705.08	GRPA	5
146	11375517	DEU	F	760.83	GRPA	4
147	11377836	BRA	M	2255.00	GRPA	13
148	11385342	USA	F	0.00	GRPA	2
149	11389384	TUR	F	221.12	GRPB	2
150	11390712	USA	M	1571.61	GRPB	3
151	11391039	GBR	M	3594.30	GRPA	6
152	11392327	USA	M	476.33	GRPA	2
153	11394519	TUR	M	960.75	GRPA	6
154	11395067	USA	F	799.27	GRPB	4
155	11396894	DEU	F	127.51	GRPA	1
156	11397339	USA	F	966.40	GRPB	4
157	11399530	USA	M	2606.65	GRPA	6
158	11401822	DEU	M	885.61	GRPA	6
159	11404341	USA	F	1008.85	GRPB	4
160	11407267	USA	F	403.97	GRPA	3
161	11407530	BRA	F	1040.97	GRPA	4
162	11408028	CAN	F	297.14	GRPA	1
163	11409366	BRA	M	0.00	GRPB	9
164	11409754	USA	F	871.94	GRPA	4
165	11410731	DEU	F	476.31	GRPB	3
166	11411530	FRA	F	1012.36	GRPB	5
167	11411769	GBR	M	0.00	GRPB	1
168	11415862	USA	M	817.45	GRPB	4
169	11424954	GBR	M	540.92	GRPA	2
170	11427899	USA	M	706.53	GRPA	3
171	11432912	USA	M	1372.78	GRPB	2
172	11437590	MEX	F	0.00	GRPB	9
173	11439684	BRA	M	3263.59	GRPA	7
174	11440747	BRA	M	1369.65	GRPA	4
175	11443706	USA	F	3823.43	GRPB	8
176	11444955	FRA	F	1828.14	GRPA	6
177	11456339	FRA	F	868.34	GRPA	2
178	11457602	USA	F	2855.28	GRPB	8
179	11458476	DEU	F	1057.00	GRPB	2
180	11459499	CAN	M	1368.02	GRPB	4
181	11460549	BRA	M	1780.84	GRPA	4
182	11465113	BRA	F	482.61	GRPB	2
183	11465121	USA	M	1633.04	GRPB	4
184	11466157	FRA	M	750.81	GRPA	6
185	11466228	CAN	F	930.22	GRPB	2
186	11466295	BRA	M	771.48	GRPB	3
187	11467374	BRA	M	0.00	GRPB	9
188	11468739	USA	M	620.63	GRPA	3
189	11469061	USA	M	1098.64	GRPB	3
190	11470372	DEU	M	2583.54	GRPB	4
191	11470709	ESP	M	820.10	GRPB	5
192	11471111	BRA	M	2524.30	GRPB	11
193	11471379	BRA	M	2360.44	GRPB	5
194	11473667	USA	F	3088.86	GRPB	9
195	11476141	USA	M	422.26	GRPA	1
196	11476957	TUR	M	4057.20	GRPB	13
197	11479800	USA	M	601.94	GRPA	1
198	11489269	DEU	F	1123.17	GRPB	2
199	11490791	TUR	M	937.98	GRPA	6
200	11492194	USA	M	540.31	GRPB	1
201	11492633	DEU	M	1212.77	GRPB	7
202	11493002	DEU	M	2887.37	GRPA	5
203	11494006	DEU	M	751.65	GRPB	2
204	11496357	MEX	F	819.40	GRPB	2
205	11498043	USA	F	2053.19	GRPB	6
206	11499790	USA	F	398.37	GRPB	1
207	11500020	CAN	F	365.23	GRPB	1
208	11500795	TUR	M	1456.22	GRPA	8
209	11502793	DEU	F	0.00	GRPA	13
210	11505090	CAN	M	441.99	GRPB	4
211	11506332	TUR	M	0.00	GRPB	1
212	11510281	GBR	M	3264.44	GRPB	12
213	11514966	USA	F	401.55	GRPA	3
214	11516867	USA	M	1771.88	GRPB	3
215	11517365	FRA	M	465.51	GRPB	8
216	11519227	BRA	F	0.00	GRPB	8

Showing 1 to 24 of 45,883 entries, 6 total columns

Velo.com is a UK-based online retailer of bikes and biking equipment with customers around the world. The company's business model is to encourage extensive product customization: customers are able to configure bikes to their exact specifications from a wide selection of derailleurs, brakes, handlebars, seats, frames, wheels, etc.. About a year ago one of the company's business analysts, Sarah Swan, noticed that customers seemed to be dropping off during the checkout process, especially when attempting to purchase complicated and potentially expensive custom bikes. She observed that such customers often visited the website multiple times to configure their bikes, and expected to see a relatively lower nonpurchase rate for them, given their investment of time and effort. She was surprised to find that they actually had a higher nonpurchase rate compared to customers with fewer visits. She reviewed the checkout system carefully, doing process modeling to try to find the problem, which, unfortunately, was not totally obvious. There seemed to be a constellation of issues with the cart system. Customers were able to save the contents of their carts, but it appeared that sometimes, a revision to the cart caused all the items to be erased. These customers would have to start over, and, in frustration, some didn't. There appeared to be some other problems as well, but this was the main one she brought to the attention of her boss, the Director of Analytics. After lengthy discussions, the IT department at velo.com re-engineered the cart system and created a revised version of the website. However, the CTO, being skeptical that there was a problem with the original version, was reluctant to simply switch systems, and lobbied for an A/B test before committing to the new system. Given the high stakes, the experiment was carefully designed. After logging in, customers would be randomly assigned to either the original checkout system or the revised system. For every subsequent visit, customers would be presented with the same system. The experiment was run for one month. At the end of that month, Sarah had plenty of data to analyze. She needs to recommend definitively whether to switch systems. What should she recommend?

1-Plot the distribution of `spent` for the control (GRP A) and treatment (GRP B) groups using the facet function below. Comment on the best measure of central tendency. Do mean and standard deviation have much meaning in this distribution?

2- summary table with the n, mean, median, standard deviation of `spent` by group (i.e., present these statistics for GRP A and GRP B separately). Include also a calculation of the the proportion of non-purchases in each group. 3-s spending significantly different in the treatment (B) group? Comment also on the magnitude of the difference in spending between the two groups (in addition to statistical significance).

Use Bootstrapping. Hint: compare the medians. What is the null hypothesis for this comparison?

4- Is the proportion of nonpurchase statistically different in the treatment group? Compare the mean purchase rate is GRP A and GRP B. Comment also on the magnitude of the difference in purchase rate between the two groups (in addition to statistical significance).

What is the null hypothesis for this comparison?

5-course of action should Sarah recommend to the management at velo.com?