org.statcato.statistics.inferential
Class CIOnePopMeanSigmaUnknown

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

public class CIOnePopMeanSigmaUnknown
extends ConfidenceInterval

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

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

Field Summary
 
Fields inherited from class org.statcato.statistics.inferential.ConfidenceInterval
center, confidenceLevel
 
Constructor Summary
CIOnePopMeanSigmaUnknown(double confidenceLevel, int n, double mean, double s)
          Constructor.
 
Method Summary
 double criticalValue()
          Returns the critical value corresponding to the given confidence level.
 double getN()
          Returns the sample size.
 double getStdev()
          Returns the sample 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

CIOnePopMeanSigmaUnknown

public CIOnePopMeanSigmaUnknown(double confidenceLevel,
                                int n,
                                double mean,
                                double s)
Constructor.

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

marginOfError

public double marginOfError()
Returns the margin of error. E = t_(alpha/2) * s / 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 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

getStdev

public double getStdev()
Returns the sample standard deviation.

Returns:
sample standard deviation

getN

public double getN()
Returns the sample size.

Returns:
sample size