Rank Regression for a Multiple Regression Y_i = mu + Sum(j=1,p) X_{ij} beta_j + error_i Specialized to p=1, so Y_i = beta*X_i + mu See Sections 9.6-9.7 in text Data: Amount of pre-packed engine lubricant and engine survival times: (Source of data unknown.) Lubricant Survival Lubricant Survival 1. 29 23 11. 84 429 2. 21 36 12. 37 489 3. 30 67 13. 94 504 4. 45 104 14. 56 925 5. 48 147 15. 67 980 6. 92 164 16. 79 1254 7. 74 247 17. 70 2961 8. 61 304 18. 93 5351 9. 99 355 19. 76 9915 10. 24 408 20. 72 11301 Let X=Lubricant and Y=Survival (in days) Within-sample tie groups: X: 0 Y: 0 NO TIES in Xs or Ys Finding the minimum value of D(beta): nw=190 nodes ranging from -5527 to 5187 Slope for beta<-5527: -2791.5 for beta>5187: 2791.5 Finding the lowest point on the curve Y = D(beta): At minimum value, lslope=-31.5 rslope=32.5 Qsum=2791.5 Minimum attained at beta=6.82813 D(beta)=256469 Intercept: mu=197.914 (median of Y_i-beta X_i Walsh averages) Regression line and errors: E1 is mean of absolute values of residuals E2 is root-mean-square of residuals Rank-Regression: Y = 6.8281 X + 197.914 E1=1615.16 E2=3355.82 See TheilRegression.txt for the corresponding results for Theil`s and least-squares regressions.