import javastat.survival.regression.CoxRegression;

/**

*

* <p>Example: class CoxRegression.</p>

* <p>Data Source: Collett, D. (1994). Modelling Survival Data in Medical

* Research. New York: Chapman and Hall, pp. 290-291. </p>

*/

double[] time = {156, 1040, 59, 421, 329, 769, 365, 770, 1227, 268, 475,

1129, 464, 1206, 638, 563, 1106, 431, 855, 803, 115,

744, 477, 448, 353, 377};

double[] censor = {1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1,

0, 0, 1, 0, 0, 0, 1, 0};

double[][] covariate = { {1, 1, 1, 2, 1, 2, 2, 2, 2, 1, 2, 2, 2, 2, 1,

2, 1, 1, 1, 1, 1, 2, 1, 1, 2, 2},

{66, 38, 72, 53, 43, 59, 64, 57, 59, 74, 59,

53, 56, 44, 56, 55, 44, 50, 43, 39, 74, 50,

64, 56, 63, 58} };

testclass1 = new CoxRegression(0.05, time, censor, covariate);

coefficients = testclass1.coefficients;

variance = testclass1.variance;

testStatistic = testclass1.testStatistic;

pValue = testclass1.pValue;

confidenceInterval = testclass1.confidenceInterval;

print("The estimated coefficients (non-null constructor) = [" +

coefficients[0] + " , " + coefficients[1] + "]");

print("The p-values (non-null constructor) = [" +

pValue[0] + " , " + pValue[1] + "]");

testclass2 = new CoxRegression();

coefficients = testclass2.coefficients(time, censor, covariate);

testStatistic = testclass2.testStatistic(time, censor, covariate);

pValue = testclass2.pValue(time, censor, covariate);

confidenceInterval = testclass2.confidenceInterval(0.1, time, censor, covariate);

print("The test statistics (null constructor) = [" +

testStatistic[0] + " , " + testStatistic[1] + "]");

print("The confidence interval for b1 (null constructor) = [" +

confidenceInterval[0][0] + " " + confidenceInterval[0][1] + "]");

print("The confidence interval for b2 (null constructor) = [" +

confidenceInterval[1][0] + " " + confidenceInterval[1][1] + "]");

Results:

The estimated coefficients based on non-null constructor = [-0.796 , 0.147]

The p-values for the test based on non-null constructor = [0.209 , 0.0010]

The test statistics based on null constructor = [-1.258 3.196]

The confidence interval for the first parameter based on null constructor

= [-1.837 , 0.245]

The confidence interval for the second parameter based on null constructor

= [0.071 0.222]