IE Reverses Logic

While the following code works in Firefox and Mozilla,
IE6 reverses the logic (when I click yes on the top it checks no on the
bottom and vice versa).

<form method="POST">
<p>
<input type="radio" name="decide" value="yes"
onchange="decide1[0].checked = decide[0].checked">yes
<input type="radio" name="decide" value="no"
onchange="decide1[1].checked = decide[1].checked">no.</font></p>
<p>
[...]</p>
<p>
<input type="radio" name="decide1" value="yes"
onchange="decide[0].checked = decide1[0].checked">yes
<input type="radio" name="decide1" value="no"
onchange="decide[1].checked = decide1[1].checked">no.</p>
<p>
<input type="submit" value="Submit"><input type="reset"
value="Reset"></p>
</form>

Please advise.