Physicians are recommending more exercise for patients, especially those who are overweight. One benefit of regular exercise is thought to be a reduction of bad cholesterol. To study the relationship, a doctor selected a sample of patients who did not do regular exercise, and measured their cholesterol level. She then started the patients on a program of exercise, and asked them to record the number of minutes per week that they exercised. After 4 months, she re-measured their cholesterol levels. The data are contained in the file Cholesterol.xls.

a)Plot the data. Does it appear that amount of exercise and cholesterol level change is related?

b)Determine the regression equation relating cholesterol reduction (dependent variable) to amount of exercise (independent variable), and find a 95% confidence interval for the independent variable. Provide a brief and meaningful written interpretation of the intercept and slope coefficients and the confidence interval.

c)Can we conclude that exercise affects the change in cholesterol level of the exerciser?

d)How well does the linear model fit this data?Justify your response using the regression output.

Patient Exercise Chol. Level Chol. Level Reduction # (min/week) Before After 119 216 170 46 122 233 204 29 487 251 195 56 147 251 226 25 388 283 239 44 JOONOUT A WN. 348 210 198 12 206 257 229 28 86 210 212 -2 272 282 251 31 305 202 173 29 11 331 209 188 21 12 271 267 228 39 13 297 274 246 28 14 422 201 159 42 15 210 272 242 30 16 436 255 219 36 17 460 297 258 39 18 207 237 224 13 19 106 249 234 15 20 404 254 217 37 21 339 245 217 28 22 112 225 210 15 23 204 248 222 26 24 181 226 231 -5 25 188 268 250 18 26 332 289 253 36 27 422 236 200 36 28 106 203 192 11 29 369 227 195 32 30 96 254 250 4 31 325 206 168 38 32 481 224 182 42 33 259 209 163 46 34 143 283 243 40 35 261 248 226 22 36 301 231 186 45 37 106 253 248 5 38 447 258 205 53 39 372 207 164 43 40 373 238 207 31 41 227 275 260 15 42 351 272 243 29 43 163 251 243 8 44 350 284 269 15 45 166 241 241 0 46 215 232 202 30 47 337 218 191 27 48 451 264 208 56 49 244 293 276 17 50 112 243 214 29