<?xml version="1.0" encoding="utf-8" standalone="no"?>
<!DOCTYPE document PUBLIC "-//CNX//DTD CNXML 0.5 plus MathML//EN" "http://cnx.rice.edu/cnxml/0.5/DTD/cnxml_mathml.dtd">
<document xmlns="http://cnx.rice.edu/cnxml" xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="m11211">

  <name>Balance Scale Simulation</name>

  <metadata>
  <md:version>1.3</md:version>
  <md:created>2003/05/30</md:created>
  <md:revised>2003/07/18 10:34:45.792 GMT-5</md:revised>
  <md:authorlist>
    <md:author id="dmlane">
      <md:firstname>David</md:firstname>
      
      <md:surname>Lane</md:surname>
      <md:email>lane@rice.edu</md:email>
    </md:author>
  </md:authorlist>

  <md:maintainerlist>
    <md:maintainer id="dmlane">
      <md:firstname>David</md:firstname>
      
      <md:surname>Lane</md:surname>
      <md:email>lane@rice.edu</md:email>
    </md:maintainer>
    <md:maintainer id="mjeanes">
      <md:firstname>Matthew</md:firstname>
      
      <md:surname>Jeanes</md:surname>
      <md:email>mjeanes@rice.edu</md:email>
    </md:maintainer>
  </md:maintainerlist>
  
  

  <md:abstract/>
</metadata>

  <content>
    <para id="beginby">
      Begin by answering the questions, even if you have to guess. The
      first time you answer the questions you will not be told whether
      you are correct or not.
    </para>

    <para id="onceyou">
      Once you have answered all the questions, answer them again
      using the simulation to help you. This time you will get
      feedback about each individual answer.
    </para>

    <para id="showsim">
      <cnxn target="genins">Show Simulation</cnxn>
    </para>

    
    <media type="application/x-java-applet" src="questionbase.questionBase.class">
      <param name="ARCHIVE" value="questionbase.jar"/>
      <param name="width" value="480"/>
      <param name="height" value="430"/>
      <param name="XML" value="balance.xml"/>
      <param name="Background" value="16777164"/>
		<param name="FontSize" value="14"/>
      <param name="EndInfo" value="Please use the simulation to help you discover and understand the answers to the questions."/>
    </media>
    
  <section id="genins">
    <name>General Instructions</name>
    <para id="thisdem">
      This demonstration allows you to change the shape of a
      distribution and see the point at which the distribution would
      balance. The graph is a histogram of 600 scores. The mean,
      median, and mode are all equal to 8. You can see that the
      histogram is balanced on the tip of the triangle.
    </para>

    <para id="youcan">
      You can change the shape of the histogram by painting with the
      mouse. Notice that the triangle beneath the X-axis automatically
      moves to the point where the histogram is balanced. Experiment
      with different shapes and see if you can determine whether there
      is a relationship between the mean, median, and/or the mode and
      the location of the balance point.
    </para>
    </section>

    <section id="stepbystep">
      <name>Step by Step Instructions</name>
      <para id="link">
	<cnxn target="toptable">Show Questions</cnxn>
      </para>

      <para id="firstdraw">
	First, draw a distributon with a positive skew such as the
	distribution shown below. The mean, median, and mode will not
	be equal for a skewed distribution. Note which statistic is
	highest and which is lowest. Which one is the point where the
	distribution is balanced?
      </para>

      <para id="pic1">
	<media type="image/png" src="balance_demo.png"/>
      </para>

      <para id="nowdraw">
	Now draw a distributon with a negative skew.
      </para>

      <para id="pic2">
	<media type="image/png" src="balance_demo2.png"/>
      </para>

      <para id="comparethe">
	Compare the statistics for this distributon, and see which one
	corresponds to the balance point.
      </para>

      <para id="experiment">
	Experiment with different distributions and see if you have
	discovered a rule for the balance point that holds for all
	distributions you try.
      </para>

      <media type="application/x-java-applet" src="balancebasic.mean_balance.class">
	<param name="archive" value="balancebasic.jar"/>
	<param name="width" value="470"/>
	<param name="height" value="375"/>
	<param name="name" value="balancebasic"/>
      </media>
    </section>

    <section id="summary">
      <name>Summary</name>
      <para id="summ">
	For every distribution, the balance point is the mean.
      </para>
    </section>  
  </content>
  
</document>
