org.statcato.statistics.inferential

Class CI2PopMeanSigmaKnown

java.lang.Object

org.statcato.statistics.inferential.ConfidenceInterval

org.statcato.statistics.inferential.CI2PopMeanSigmaKnown

public class CI2PopMeanSigmaKnown
extends ConfidenceInterval

Confidence interval class for two population mean, sigma (population standard deviation) known.

Since:

1.0

Constructor Summary

Constructors

Constructor and Description
CI2PopMeanSigmaKnown(double confidenceLevel, int n1, int n2, double xBar1, double xBar2, double sigma1, double sigma2) Constructor

Method Summary

Modifier and Type	Method and Description
double	criticalValue() Returns the critical value corresponding to the given confidence level.
double	marginOfError() Returns the margin of error.

Methods inherited from class org.statcato.statistics.inferential.ConfidenceInterval

center, lowerLimit, toString, upperLimit

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CI2PopMeanSigmaKnown

public CI2PopMeanSigmaKnown(double confidenceLevel,
                            int n1,
                            int n2,
                            double xBar1,
                            double xBar2,
                            double sigma1,
                            double sigma2)

Constructor

Parameters:

confidenceLevel - confidence level, between 0 and 1

n1 - sample size 1

n2 - sample size 2

xBar1 - sample mean 1

xBar2 - sample mean 2

sigma1 - population standard deviation 1

sigma2 - population standard deviation 2

Method Detail

marginOfError

public double marginOfError()

Returns the margin of error. E = z_(alpha/2) * sqrt(sigma1^2 / n1 + sigma2^2 / n2)

Specified by:

marginOfError in class ConfidenceInterval

Returns:

margin of error

criticalValue

public double criticalValue()

Returns the critical value corresponding to the given confidence level. Uses Student's t distribution to find t_(alpha/2), where alpha is the significance level (1 - confidence level).

Specified by:

criticalValue in class ConfidenceInterval

Returns:

critical value