Re: how to test if the variance of difference is smaller than another group?

Lee Sander wrote:
Hi,
I have the following problem on which I would appreciate some
assistance.

I have two groups of people--some are Europeans while others are
Americans.
I am comparing how they perform some basic math problem during
different times of
the day (say, morning versus evening ) (i can describe their
performance by a positive real number).

On x-axis I plot their age and on y-axis I plot the similarity in
their performance during the two
times of the day (I measure similarity by computing the difference
between the scores received
during the two evaluations). I bin the ages: so I group people of age
25 to 29 in one bin, then
I bin 30 to 34 into another bin, and so forth.
I want to test if one of the groups show a larger difference in
performance than the other.
Please let me know if I can clarify the problem further.
thanks
Lee

Lee, why bin the ages? I'd look at a scatter-plot with X = actual age, and two different symbols for Europeans & Americans. The nature of that plot should be informative about what kind of model you need to create.

--
Bruce Weaver
bweaver@xxxxxxxxxxxx
www.angelfire.com/wv/bwhomedir
"When all else fails, RTFM."
.

Relevant Pages

  • Re: OT - The Hydroplaning Economy
    ... The military and intelligence services of many countries are ... I have no idea where Bin Ladin is hiding out but you can ... Americans, and that Americans are an easy kill. ... As long as we fight in Iraq and demonstrate our staying power, ...
    (rec.outdoors.rv-travel)
  • Re: OT - The Hydroplaning Economy
    ... I have no idea where Bin Ladin is hiding out but you can bet your ass that he has his focus on Afghanistan where he has a much better chance of furthering his campaign of attacking the infidels. ... All he needs to do is to convince about 1 1/2% of Muslims that it is their religious duty to kill Americans, and that Americans are an easy kill. ... As long as we fight in Iraq and demonstrate our staying power, we make it harder for him to claim progress. ...
    (rec.outdoors.rv-travel)
  • Re: Histogram Functions
    ... Count the number of data that fall into each bin (either ... > the age distribution of the inhabitants. ... > With this data the following command in MATLAB: ...
    (comp.soft-sys.matlab)
  • Re: Histogram Functions
    ... Count the number of data that fall into each bin (either defined ... A vector of length 50,000 containing the age of each ... With this data the following command in MATLAB: ...
    (comp.soft-sys.matlab)
  • how to test if the variance of difference is smaller than another group?
    ... On x-axis I plot their age and on y-axis I plot the similarity in ... times of the day (I measure similarity by computing the difference ... I bin the ages: so I group people of age ...
    (sci.stat.edu)