***simple simulation of what it means when I am regressing evggfp on Y. what does the transformation mean?. get fILE='C:\aging\fRAILTY\frailty_data\simul_01.sav'. compute physical = 100 - 5*age. compute mental = 100 - 10*age. Compute X1 = physical. Compute Y1 = mental. compute Y2 = .5*physical + .5*mental. compute y3 = .25*physical + .75 * mental. compute y4 = .75*physical + .25 * mental. ***********************. x and y conditionally independent. Y1 = mental. regression /dependent = x1/enter y1. **constant = 50. **coeff = .5 . temporary. select if (age le 10). regression /dependent = x1/enter y1. **constant = 50. **coeff = .5 . ***no change. varying t does not actually matter. ******************************. x and y are correlated. Y2 = .5*physical + .5*mental. regression /dependent = x1/enter y2. **constant = 33.333. **coeff = .667. ******************************. x and y are correlated. y3 = .25*physical + .75 * mental. regression /dependent = x1/enter y3. **constant = 42.857. **coeff = .571. ******************************. x and y are correlated. y4 = .75*physical + .25 * mental. regression /dependent = x1/enter y4. **constant = 20. **coeff = .8. ***** coefficients and constant and slope. regress x on y. * x Y. * phys Mental constant slope * 0 1 50 .5 * .25 .75 42.857 .571 * .5 .5 33.33 .667 * .75 .25 20 .8 * 1 0 0 1 * . ************* NOW I WILL USE DIFFERENT SLOPES FOR X AND Y. hARDLY ANY CHANGE IN PHYSICAL WITH AGE. get fILE='C:\aging\fRAILTY\frailty_data\simul_01.sav'. compute physical = 100 - 1*age. compute mental = 100 - 10*age. Compute X1 = physical. Compute Y1 = mental. compute Y2 = .5*physical + .5*mental. compute y3 = .25*physical + .75 * mental. compute y4 = .75*physical + .25 * mental. ***********************. x and y conditionally independent. Y1 = 0* PHYS + 1 * mental. regression /dependent = x1/enter y1. **constant = 90. **coeff = .1 . ******************************. x and y are correlated. y3 = .25*physical + .75 * mental. regression /dependent = x1/enter y3. **constant = 87.097. **coeff = .129. ******************************. x and y are correlated. Y2 = .5*physical + .5*mental. regression /dependent = x1/enter y2. **constant = 81.818. **coeff = .182. ******************************. x and y are correlated. y4 = .75*physical + .25 * mental. regression /dependent = x1/enter y4. **constant = 69.231. **coeff = .308. ***** coefficients and constant and slope. regress x on y. hARDLY ANY CHANGE IN PHYSICAL WITH AGE. * x Y. * phys Mental constant slope * Y1 0 1 90 .1 * Y3 .25 .75 87.097 .129 * Y2 .5 .5 81.818 .182 * Y4 .75 .25 69.231 .308 * -- 1 0 0 1 * . ************* NOW I WILL USE DIFFERENT SLOPES FOR X AND Y. hARDLY ANY CHANGE IN MENTAL WITH AGE. get fILE='C:\aging\fRAILTY\frailty_data\simul_01.sav'. compute physical = 100 - 5*age. compute mental = 100 - 1*age. Compute X1 = physical. Compute Y1 = mental. compute Y2 = .5*physical + .5*mental. compute y3 = .25*physical + .75 * mental. compute y4 = .75*physical + .25 * mental. ***********************. x and y conditionally independent. Y1 = 0* PHYS + 1 * mental. regression /dependent = x1/enter y1. **constant = -400. **coeff = 5 . ******************************. x and y are correlated. y3 = .25*physical + .75 * mental. regression /dependent = x1/enter y3. **constant = -150. **coeff = 2.5. ******************************. x and y are correlated. Y2 = .5*physical + .5*mental. regression /dependent = x1/enter y2. **constant = -66.67. **coeff = 1.667.. ******************************. x and y are correlated. y4 = .75*physical + .25 * mental. regression /dependent = x1/enter y4. **constant = -25. **coeff =1.25. ***** coefficients and constant and slope. regress x on y.hARDLY ANY CHANGE IN MENTAL WITH AGE. * x Y. * phys Mental constant slope * Y1 0 1 -400. 5 * Y3 .25 .75 -150 2.5 * Y2 .5 .5 -66.67 1.667 * Y4 .75 .25 -25 1.25 * -- 1 0 0 1 * .