Player First Round Final Round Differences Michael Letzig 75 71 4 Scott Verplank 74 76 -2 D.A. Points 77 72 5 Jerry Kelly 73 76 -3 Soren Hansen 67 70 -3 D.J. Trahan 69 74 -5 Bubba Watson 66 77 -11 Reteif Goosen 77 71 6 Jeff Klauk 67 74 -7 Kenny Perry 75 72 3 Aron Price 71 67 4 Charles Howell 75 66 9 Jason Dufner 72 76 -4 Mike Weir 72 70 2 Carl Pettersson 74 71 3 Bo Van Pelt 65 77 -12 Ernie Els 73 70 3 Cameron Beckman 73 69 4 Nick Watney 67 69 -2 Tommy Armour III 75 68 7 T Test: Paired Two Sample for Means First Round Final Round Mean 71.85 71.8 Variance 14.02894737 11.32631579 Observations 20 20 Pearson Correlation -0.353231875 Hypothesized Mean Difference 0 df 19 t Stat 0.038202166 P(T<=t) one-tail 0.484962523 t Critical one-tail 1.729132793 P(T<=t) two-tail 0.969925046 t Critical two-tail 2.093024022 What is the margin of error for a 90% confidence interval estimate for the difference between the population means