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Table 2 The empirical type I error rates of the tests at the significance level 0.05 when the survival times have uniform, exponential, log-normal,uniform and exponential, uniform and log-normal, or exponential and log-normal distributions with equal medians but unequal variances and sample sizes n 1 = 100, n 2 = 150, n 3 = 150, n 4 = 200

From: Comparing survival curves based on medians

Distributions and parameters

Censoring rate

BC

TJ

New

Uniform distribution

  θ = (10,10,10,10)

  a = (4,4,4,4)

  c = (2,3,4,5)

0

0.061

0.057

0.058

0.1

0.057

0.068

0.053

0.2

0.061

0.089

0.054

0.3

0.062

0.109

0.053

Exponential distribution

  θ = (10-2log(2),10-3log(2),

  10-4log(2),10-5log(2))

  a = (1/2,1/3,1/4,1/5)

0

0.060

0.057

0.058

0.1

0.067

0.071

0.062

0.2

0.062

0.079

0.057

0.3

0.064

0.098

0.057

Log-normal distribution

  θ = (log(10), log(10), log(10), log(10))

  a = (0.2, 0.3, 0.4, 0.5)

0

0.057

0.053

0.055

0.1

0.063

0.073

0.059

0.2

0.064

0.094

0.058

0.3

0.060

0.117

0.054

Two uniform and two exponential distributions

  θ = (10, 10, 10-10log(2),10-10log(2))

  a = (0.1, 0.1, 0.1, 0.1)

  c = (0.01, 0.01, 0.01, 0.01)

0

0.055

0.050

0.052

0.1

0.053

0.080

0.047

0.2

0.055

0.102

0.049

0.3

0.059

0.118

0.051

Two uniform and two log-normal distributions

  θ = (10,10, log(10), log(10))

  a = (5,5,0.3,0.3)

  c = (2,2,2,2)

0

0.058

0.081

0.054

0.1

0.063

0.087

0.057

0.2

0.061

0.107

0.054

0.3

0.055

0.123

0.048

Two log-normal and two exponential distributions

  θ = (log(10), log(10),10-log(2)/0.3,10-log(2)/0.3)

  a = (0.3,0.3,0.3,0.3)

0

0.052

0.049

0.049

0.1

0.050

0.058

0.047

0.2

0.058

0.082

0.054

0.3

0.056

0.095

0.050