ks.test ; impossible to calculate exact exact value with ex-aequos
Hello, That is a warning, not an error. And it documented. In ?ks.test, section Details, the relevant part is The presence of ties always generates a warning, since continuous distributions do not generate them. If the ties arose from rounding the tests may be approximately valid, but even modest amounts of rounding can have a significant effect on the calculated statistic. It then adds, three paragraphs down: Exact p-values are not available for the two-sample case if one-sided or in the presence of ties. You can use exact = FALSE but it will still issue a warning. ks.test(a, b, exact = FALSE) Two-sample Kolmogorov-Smirnov test data: a and b D = 0.58333, p-value = 0.0337 alternative hypothesis: two-sided Warning message: In ks.test(a, b, exact = FALSE) : p-value will be approximate in the presence of ties Hope this helps, Rui Barradas ?s 21:17 de 10/12/2018, Fatma Ell escreveu:
Dear all, I'm trying to use ks.test in order to compare two curve. I've 0 values i think this is why I have the follonwing warnings :impossible to calculate exact exact value with ex-aequos a=c(3.02040816326531, 7.95918367346939, 10.6162790697674, 4.64150943396226, 1.86538461538462, 1.125, 1.01020408163265, 1.2093023255814, 0.292452830188679, 0, 0, 0) b=c(2.30769230769231, 4.19252873563218, 5.81924882629108, 6.2248243559719, 5.02682926829268, 4.50728862973761, 3.61741424802111, 5.05479452054795, 3.68095238095238, 1.875, 5.25, 0) ks.test(a,b) data: a and b D = 0.58333, p-value = 0.0337 alternative hypothesis: two-sided Warning message: In ks.test(a, b) : impossible to calculate exact exact value with ex-aequos Does the p-value is correct ? Otherwise, how to solve this issue ? Thanks a lot. [[alternative HTML version deleted]]
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