def testEvalNormalCdf(self):
p = thinkstats2.EvalNormalCdf(0)
self.assertAlmostEqual(p, 0.5)
p = thinkstats2.EvalNormalCdf(2, 2, 3)
self.assertAlmostEqual(p, 0.5)
p = thinkstats2.EvalNormalCdf(1000, 0, 1)
self.assertAlmostEqual(p, 1.0)
p = thinkstats2.EvalNormalCdf(-1000, 0, 1)
self.assertAlmostEqual(p, 0.0)
x = thinkstats2.EvalNormalCdfInverse(0.95, 0, 1)
self.assertAlmostEqual(x, 1.64485362695)
x = thinkstats2.EvalNormalCdfInverse(0.05, 0, 1)
self.assertAlmostEqual(x, -1.64485362695)
def Percentile(self, p):
"""Inverse CDF of p.
p: percentile rank 0-100
"""
return thinkstats2.EvalNormalCdfInverse(p / 100, self.mu, self.sigma)