Cosmetic surgery study. Data files cosmetic_surgery.sav (spss file) and cosmetic_surgery.xlsx (excel data file) contain data from a hypothetical study of quality of life of cosmetic surgery patients (data file from A. Field). Variables include BDI (Beck Depression Inventory score with possible range 0-63, higher score indicating greater depression symptomotology), Base_QOL (quality of life score at baseline with higher score indicating greater perceived QOL), and Post_QOL (QOL score at followup). Coding for categorical variables is the following: Surgery 0=waiting list 1=surgery

1. Research Question: Is there a significant difference in the quality-of-life (QOL) scores between cosmetic surgery patients who underwent surgery?

2. Examine data characteristics that could affect the appropriateness of your choice of analysis method and/or how you interpret results (e.g. missing data, normal distributions, outliers).

3. Give measurement level of each variable in the analysis; include an example of at least one of the relevant descriptive stats (e.g. something you've used to determine if lots of missing data or substantial non-normality; means on the dependent variable by group to help interpret results, etc.)

4. Examine assumptions of method/model (if there are any in addition to measurement level). Examine major assumptions and what could be done to remedy if serious violation.

5. Summarize and interpret results in relation to the research question/hypothesis stated in question #1 above. Use results to answer research question, interpreting major results details (e.g. not just model significance, but also what coefficients mean, magnitude and direction of differences, etc.)

6. Further examine issues that might affect the interpretation of results. Comment on any data or analysis issues you can identifydo further examination on at least one issue or analysis extension (e.g. post hoc comparisons, estimating reduced or alternative model).

7. Apply the following statistical methods:

1. t-test to assess assess the difference between 2 means - Post-QOL and Base QOL.
2. Non-parametric equivalent to independent t-test (Mann-Whitney).

ID	Post_QoL	Base_QoL	Surgery
9	61.5	80.0	1
18	61.1	73.0	1
19	56.0	66.0	1
20	63.0	61.0	1
27	72.0	73.0	1
35	68.3	72.0	1
36	65.0	73.0	1
37	70.7	70.0	1
38	67.0	76.0	1
50	73.9	71.0	1
51	58.0	79.0	1
52	57.0	63.0	1
53	60.0	62.0	1
54	52.0	65.0	1
55	53.0	57.0	1
56	54.4	58.0	1
57	56.0	59.0	1
58	52.0	61.0	1
59	66.0	57.0	1
60	58.0	71.0	1
61	55.0	63.0	1
69	57.0	71.0	1
70	51.0	62.0	1
71	56.0	56.0	1
72	64.0	61.0	1
73	58.0	69.0	1
74	53.0	63.0	1
75	57.3	58.0	1
76	59.0	62.0	1
77	61.0	64.0	1
89	64.7	58.0	1
90	67.0	70.0	1
96	60.2	74.0	1
97	53.0	65.0	1
98	51.0	58.0	1
100	51.0	65.0	1
101	54.0	56.0	1
104	54.0	55.0	1
108	60.4	56.0	1
109	64.0	65.0	1
110	61.0	69.0	1
112	55.0	61.0	1
113	55.0	60.0	1
115	64.0	75.0	1
116	66.0	69.0	1
118	52.0	72.0	1
119	52.0	57.0	1
120	49.0	57.0	1
122	59.0	70.0	1
123	53.0	64.0	1
125	59.0	77.0	1
126	57.0	64.0	1
131	69.0	76.0	1
132	64.0	74.0	1
136	68.5	61.0	1
137	54.0	74.0	1
138	71.8	59.0	1
139	65.0	77.0	1
140	67.0	70.0	1
141	70.4	72.0	1
142	62.0	75.0	1
143	64.0	67.0	1
144	63.0	69.0	1
145	53.0	68.0	1
146	55.0	58.0	1
150	67.4	57.0	1
151	57.0	72.0	1
152	58.0	62.0	1
156	62.4	65.0	1
157	59.0	67.0	1
158	63.0	64.0	1
162	62.0	53.0	1
163	68.0	67.0	1
164	73.0	73.0	1
165	60.6	78.0	1
166	59.0	66.0	1
167	60.0	64.0	1
168	63.9	65.0	1
169	56.0	69.0	1
173	49.8	53.0	1
174	52.0	55.0	1
175	55.0	57.0	1
176	63.8	60.0	1
177	53.0	69.0	1
178	47.0	58.0	1
190	53.0	53.0	1
191	56.7	58.0	1
192	48.0	62.0	1
193	48.0	53.0	1
194	56.8	53.0	1
195	53.0	62.0	1
196	56.0	58.0	1
197	66.8	61.0	1
198	51.0	72.0	1
199	53.0	56.0	1
200	61.7	58.0	1
201	51.0	67.0	1
202	54.0	56.0	1
203	63.6	59.0	1
204	60.0	69.0	1
205	59.0	65.0	1
216	47.0	65.0	1
217	49.0	52.0	1
218	63.8	54.0	1
219	53.0	69.0	1
220	58.0	58.0	1
227	57.1	57.0	1
228	65.0	62.0	1
229	66.0	70.0	1
230	68.4	71.0	1
231	58.0	73.0	1
232	62.0	63.0	1
234	46.0	59.0	1
235	50.0	51.0	1
236	67.1	55.0	1
237	60.0	72.0	1
238	67.0	65.0	1
240	68.0	68.0	1
241	68.0	73.0	1
242	66.7	73.0	1
249	62.7	56.0	1
250	57.0	68.0	1
251	57.0	62.0	1
258	73.9	59.0	1
259	57.8	79.0	1
260	52.0	63.0	1
261	60.0	57.0	1
270	53.0	63.0	1
271	66.3	58.0	1
272	55.0	71.0	1
273	64.0	60.0	1