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Weibull function in Excel
I have a survival dataset (see below). I want to fit to Weibull function
S(t)=EXP(-alpha*Time^gamma). If I use Excel Solver, alpha=0.00367 and gamma=2.32. If I use a method tranforming probability to Ln(Ln(1/S(t)) which will be a linear function of Ln (t). But I got a different alpha and gamma. When I compared two alphas adn gammas, the Solver results had a better goodness of fit. What is the problem? THanks Month Probability of survival 0 1 1 1 2 0.92 3 0.90 4 0.88 5 0.83 6 0.76 7 0.74 8 0.69 9 0.57 10 0.48 11 0.39 12 0.27 13 0.27 14 0.13 |
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