Question 1008328
<pre>
Follow directions. You are told to compute the variance of the means.
So you don't pay any attention to those individual variances.
You look at the 5 means only:  

   4.5	 
   7.2	 
   3.4	 
   9.1	 
   1.2


Add them:

   4.5	 
   7.2	 
   3.4	 
   9.1	 
   1.2
------	 
  25.4

Divide the sum by 5 to get the mean of the means.

   4.5	 
   7.2	 
   3.4	 
   9.1	 
   1.2
-------	 
5)<u>25.40</u>
   5.08


Subtract 5.08 from each of the 5 means

   4.5-5.08=-0.58	 
   7.2-5.08= 2.12	 
   3.4-5.08=-1.68	 
   9.1-5.08= 4.02	 
   1.2-5.08=-3.88
-------	 
5)<u>25.40</u>
   5.08

Square each of those:

   4.5-5.08=-0.58   (-0.58)²= 0.3364 	 
   7.2-5.08= 2.12   ( 2.12)²= 4.4944	 
   3.4-5.08=-1.68   (-1.68)²= 2.8224	 
   9.1-5.08= 4.02   ( 4.02)²=16.1604	 
   1.2-5.08=-3.88   (-3.88)²=15.0544
-------	 
5)<u>25.40</u>
   5.08

Add those up:

   4.5-5.08=-0.58   (-0.58)²= 0.3364 	 
   7.2-5.08= 2.12   ( 2.12)²= 4.4944	 
   3.4-5.08=-1.68   (-1.68)²= 2.8224	 
   9.1-5.08= 4.02   ( 4.02)²=16.1604	 
   1.2-5.08=-3.88   (-3.88)²=15.0544
-------	                     ------- 
5)25.40                      38.8680
   5.08

Divide 38.8680 by 1 less than 5, which is 4:

   4.5-5.08=-0.58   (-0.58)²= 0.3364 	 
   7.2-5.08= 2.12   ( 2.12)²= 4.4944	 
   3.4-5.08=-1.68   (-1.68)²= 2.8224	 
   9.1-5.08= 4.02   ( 4.02)²=16.1604	 
   1.2-5.08=-3.88   (-3.88)²=15.0544
-------	                     ------- 
5)<u>25.40</u>                    4)<u>38.8680</u>
   5.08                       <font color="red"><b>9.7170</b></font>

That number in red is the variance of the means.

Edwin</pre>