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Fig. 1 | BMC Medical Research Methodology

Fig. 1

From: A non-linear optimisation method to extract summary statistics from Kaplan-Meier survival plots using the published P value

Fig. 1

A comparison of the absolute error associated with ln (HR) and var. ln (HR) calculated using the Parmar and nlopt method (exact and non-exact P value). The ln (HR) and var. ln (HR) were estimated from 13 KM plots using the Parmar and nlopt method (exact and non-exact P value). The absolute error was then calculated from the known, actual values published in each article. The graph represents ln (HR) (a) and var. ln (HR) (b) of each individual study calculated using each method with the horizontal line in each column equal to the mean. The statistical significance was assessed using a one-way ANOVA with Kruskal-Wallis multiple comparisons test. ** = P < 0.01, ns = P > 0.05

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BMC Medical Research Methodology

ISSN: 1471-2288

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