org.statcato.statistics.inferential
Class SampleSizeDetermination

java.lang.Object
  extended by org.statcato.statistics.inferential.SampleSizeDetermination

public class SampleSizeDetermination
extends java.lang.Object

Functions for determining the sample size estimating a population statistic.

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

Constructor Summary
SampleSizeDetermination()
           
 
Method Summary
static int mean(double alpha, double stdev, double error)
          Returns the sample size for estimating a population mean given the significance level, standard deviation, and margin of error.
static int proportion(double alpha, double estimate, double error)
          Returns the sample size for estimating a population proportion given the significance level, proportion estimate, and margin of error.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SampleSizeDetermination

public SampleSizeDetermination()
Method Detail

proportion

public static int proportion(double alpha,
                             double estimate,
                             double error)
Returns the sample size for estimating a population proportion given the significance level, proportion estimate, and margin of error. n = z^2 * p * q / E^2 if proportion estimate p is known (z is the critical value based on the significance level, E is the margin of error, and q is 1 - p.) n = z^2 * 0.25 / E^2 if proportion estimate is unknown

Parameters:
alpha - significance level
estimate - proportiion estimate (-1 if unknown)
error - margin of error
Returns:
sample size

mean

public static int mean(double alpha,
                       double stdev,
                       double error)
Returns the sample size for estimating a population mean given the significance level, standard deviation, and margin of error. n = [z * sigma / E]^2 where z is the critical value given the significance level, sigma is the population standard deviation, and E is the margin of error.

Parameters:
alpha - significance level
stdev - population standard deviation
error - margin of error
Returns:
sample size