A cardiologist carries out a study to compare the impact of a statin and a natural product control on serum lipids. Individuals were assigned randomly to the statin and control groups. Measurements of total cholesterol, lower-density lipids (LDL) and blood pressure were taken at diagnosis and annually thereafter. The results are given in Table X.

The aim of your investigation is to explore the data before a formal analysis.

1. Describe the strategy you will follow to achieve the aim and give a detailed plan of the steps required.
2. Execute the strategy and summarise your findings in a form suitable for the cardiologist.

You should consider which tabular and/or diagrammatical representation best allow for comparison of the effect of the two treatments on the outcome variables (especially serum lipids). Select suitable summary measures for each variable and/or change in variable.

Year 0 (diagnosis) Year 1 follow up Year 2 follow up age total LDL BP total LDL total ID LDL BP sex treatment years mg/dl mg/dl mmHg mg/dl mg/dl mmHg mg/dl mg/dl mmHg M 73 statin 260 4.3 189 220 3.9 184 221 3.2 143 F 63 statin 251 3.9 148 231 3.9 148 230 3.7 145 3 M 75 statin 267 4 120 262 3.6 1 15 255 3.6 110 M 56 statin 259 2.7 124 219 2.3 124 201 1.6 112 M 71 control 267 4 150 247 3.6 145 232 3 114 6 M 97 control 254 4.3 130 254 3.9 129 254 3.9 122 F 40 control 266 3.3 150 255 3.1 150 246 2.9 145 M 76 control 251 3.9 118 231 3.7 1 18 211 3.7 117 C F 80 statin 273 3.7 118 263 3.7 113 243 3.7 113 10 F 76 statin 263 4.1 190 260 4.1 190 233 3.5 158 11 M 64 control 261 4 116 221 3.6 115 151 3 110 12 M 76 control 253 2.7 180 213 2.3 178 143 2.3 154 13 83 statin 269 4.3 150 249 4.1 145 249 4.1 115 14 M 49 statin 253 3.1 150 233 3 149 213 2.4 121 15 M 67 statin 251 4 145 231 3.8 140 21 1 3.6 134 16 M 73 control 259 2.7 110 251 2.7 109 225 2.5 109 17 M 71 statin 269 4.1 116 269 3.7 111 199 3.7 111 18 M 68 control 265 4.3 170 256 3.9 170 226 3.2 151 19 M 74 control 268 4.3 170 269 4.3 169 248 4.1 126 20 M 60 control 256 2.9 120 256 2.9 122 186 2.2 112 TABLE X. DATA ON THE COMPARISON OF THE EFFECTS OF STATIN AND A PLACEBO/ CONTROL ON SERUM LIPIDS