Compare Jackknife/Bootstrap methods for the slope of a regression Starting random-number seed: 123456 X-coordinate of regressions (n=10, xbar=108.400, xsse=79582.4): 2 18 34 57 60 78 134 215 229 257 REGRESSION WITH NORMAL ERRORS (n=10, mu=3, beta=3, sigma=20) Normal regression data (n=10, ybar=339.983, xbar=108.400): (2, -6.47) (18, 76.93) (34, 113.38) (57, 192.46) (60, 184.28) (78, 276.54) (134, 434.16) (215, 665.46) (229, 687.44) (257, 775.66) Least-squares estimates: BetaHat=2.994 Muhat=15.390 True values: Beta=3.000 Mu=3.000 Residual MSE=298.23 (true sigma^2=400) Standard Est(Var(betahat)): 0.00374743 True Var(betahat): 0.00502624 t(8,0.975)=2.306 (z(0.975)=1.960) CIwid=0.141 Full-sample estimates for true beta: BetaHat=2.994 95% CI (2.853, 3.136) True beta=3.000 Coverage probability of beta for 95% normal CIs (true beta=3): Normal samples of size 10: Estimated coverage = 9503/10,000 = 95.03% JACKKNIFE ESTIMATES OF BETA FOR NORMAL DATA: Jackknife record mean: 2.989 95% CI: (2.593, 3.385) Coverage probability of beta for 95% jackknife CIs (true beta=3): Normal samples of size 10: Estimated coverage = 9993/10,000 = 99.93% BOOKSTRAP RECORD ESTIMATES OF BETA FOR NORMAL DATA: Filling the bootstrap ``beta(star)'' array: Sorting the bootstrap ``beta(star)'' array: Bootstrap median bias (Obs_Beta=2.9944): 4992/10000 = 0.499 Bootstrap median and bootstrap 95% CI for beta: 2.9946 (2.8923, 3.1853) Observed beta=2.9944 Coverage probability of beta for 95% bootstrap record CIs (true beta=3): Normal samples of size 10: Estimated coverage = 9023/10,000 = 90.23% BOOKSTRAP RESIDUAL ESTIMATES OF BETA FOR NORMAL DATA: Residuals of Y = 2.994*X + 15.390: -27.853 7.637 -3.821 6.388 -10.771 27.587 17.517 6.273 -13.665 -9.293 Filling the bootstrap ``beta(star)'' array: Sorting the bootstrap ``beta(star)'' array: Bootstrap median bias (Obs_Beta=2.9944): 4907/10000 = 0.491 Bootstrap median and bootstrap 95% CI for beta: 2.9957 (2.8883, 3.1008) Observed beta=2.9944 Coverage probability of beta for 95% bootstrap residual CIs (true beta=3): Normal samples of size 10: Estimated coverage = 8796/10,000 = 87.96% REGRESSION WITH EXPONENTIAL ERRORS (n=10, mu=3, beta=3, sigma=20) Exponential regression data (n=10, ybar=358.451, xbar=108.400): (2, 37.37) (18, 75.42) (34, 105.02) (57, 187.13) (60, 183.84) (78, 370.66) (134, 422.92) (215, 677.93) (229, 720.65) (257, 803.56) Least-squares estimates: BetaHat=3.029 Muhat=30.151 True values: Beta=3.000 Mu=3.000 Residual MSE=1624.48 (true sigma^2=400) Standard Est(Var(betahat)): 0.0204125 True Var(betahat): 0.00502624 t(8,0.975)=2.306 (z(0.975)=1.960) CIwid=0.329 Full-sample estimates for true beta: BetaHat=3.029 95% CI (2.699, 3.358) True beta=3.000 Coverage probability of beta for 95% normal CIs (true beta=3): Exponential samples of size 10: Estimated coverage = 9533/10,000 = 95.33% JACKKNIFE ESTIMATES OF BETA FOR EXPONENTIAL DATA: Jackknife record mean: 3.026 95% CI: (2.653, 3.399) Coverage probability of beta for 95% jackknife CIs (true beta=3): Exponential samples of size 10: Estimated coverage = 9995/10,000 = 99.95% BOOKSTRAP RECORD ESTIMATES OF BETA FOR EXPONENTIAL DATA: Filling the bootstrap ``beta(star)'' array: Sorting the bootstrap ``beta(star)'' array: Bootstrap median bias (Obs_Beta=3.02859): 4003/10000 = 0.400 Bootstrap median and bootstrap 95% CI for beta: 3.0420 (2.8377, 3.1580) Observed beta=3.0286 Coverage probability of beta for 95% bootstrap record CIs (true beta=3): Exponential samples of size 10: Estimated coverage = 9064/10,000 = 90.64% BOOKSTRAP RESIDUAL ESTIMATES OF BETA FOR EXPONENTIAL DATA: Residuals of Y = 3.029*X + 30.151: 1.161 -9.245 -28.101 -15.655 -28.028 104.275 -13.058 -3.368 -3.046 -4.936 Filling the bootstrap ``beta(star)'' array: Sorting the bootstrap ``beta(star)'' array: Bootstrap median bias (Obs_Beta=3.02859): 5296/10000 = 0.530 Bootstrap median and bootstrap 95% CI for beta: 3.0224 (2.7841, 3.2968) Observed beta=3.0286 Coverage probability of beta for 95% bootstrap residual CIs (true beta=3): Exponential samples of size 10: Estimated coverage = 8910/10,000 = 89.10% Summary of estimates and 95% confidence intervals: True values of beta: Normal: 3 Exponential: 3 Normal, Classical t(8) 2.9944 ( 2.8532, 3.1356) Normal, Jackknife 2.9891 ( 2.5928, 3.3854) Normal, Bootstrap record 2.9946 ( 2.8923, 3.1853) Normal, Bootstrap residual 2.9957 ( 2.8883, 3.1008) Exponential, Classical t(8) 3.0286 ( 2.6991, 3.3581) Exponential, Jackknife 3.0261 ( 2.6530, 3.3992) Exponential, Bootstrap record 3.0420 ( 2.8377, 3.1580) Exponential, Bootstrap residual 3.0224 ( 2.7841, 3.2968) Summary of coverage probabilities of 95% confidence intervals: True values of beta: Normal: 3 Exponential: 3 Normal, Classical t(8) 9503/10,000 = 95.03% Normal, Jackknife 9993/10,000 = 99.93% Normal, Bootstrap record 9023/10,000 = 90.23% Normal, Bootstrap residual 8796/10,000 = 87.96% Exponential, Classical t(8) 9533/10,000 = 95.33% Exponential, Jackknife 9995/10,000 = 99.95% Exponential, Bootstrap record 9064/10,000 = 90.64% Exponential, Bootstrap residual 8910/10,000 = 89.10% Random numbers used: 4,001,309,726 Initial random-number seed: 123456