Hi all, I am using gsl_cdf_tdist_P to get a p-value for the following two arrays:
x = 1, 2, 4, 2, 3, 1, 2, 4, 2, 1, 2 y = 11, 12, 13, 12, 13, 11, 14, 11, 12, 13, 12 (2* (1-gsl_cdf_tdist_P)) returns "8.882e-16”, but I got "9.189e-16” from t.test(x,y,var.equal=T) function in R (a statistics language). It suggests that gsl_cdf_tdist_P function is not returning a precise p-value. In addition, I noticed that (2* (1-gsl_cdf_tdist_P)) doesn’t return double numbers. Instead, any p-value smaller than 1e-16 will be 0. Could someone help me with this? Thanks, Woody
