:1.  Twenty-five independent experiments of the length of a
tube have an SD of .02 inches.  If a 26th measurement were made,
it would be off the exact value of the length of the tube by <p>

a.  .0008 inches or so
 b.  .10 inches or so
 c.  .02 inches or so
 d.  .004 inches or so
 e.  .50 inches or so <p>