org.statcato.statistics.inferential
Class CIOnePopMeanSigmaKnown

java.lang.Object
  extended by org.statcato.statistics.inferential.ConfidenceInterval
      extended by org.statcato.statistics.inferential.CIOnePopMeanSigmaKnown

public class CIOnePopMeanSigmaKnown
extends ConfidenceInterval

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

Since:
1.0
Version:
%I%, %G%
Author:
Margaret Yau

Field Summary
 
Fields inherited from class org.statcato.statistics.inferential.ConfidenceInterval
center, confidenceLevel
 
Constructor Summary
CIOnePopMeanSigmaKnown(double confidenceLevel, int n, double mean, double sigma)
          Constructor.
 
Method Summary
 double criticalValue()
          Returns the critical value corresponding to the given confidence level.
 int getN()
          Returns the sample size
 double getStdev()
          Returns the standard deviation.
 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
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

CIOnePopMeanSigmaKnown

public CIOnePopMeanSigmaKnown(double confidenceLevel,
                              int n,
                              double mean,
                              double sigma)
Constructor.

Parameters:
confidenceLevel - confidence level, between 0 and 1
n - sample size
mean - sample mean
sigma - sample standard deviation
Method Detail

marginOfError

public double marginOfError()
Returns the margin of error. E = z_(alpha/2) * sigma / sqrt(n).

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 the z distribution to find z_(alpha/2), where alpha is the significance level (1 - confidence level).

Specified by:
criticalValue in class ConfidenceInterval
Returns:
critical value

getStdev

public double getStdev()
Returns the standard deviation.

Returns:
standard deviation

getN

public int getN()
Returns the sample size

Returns:
sample size