Mark
I contacted you directly to offer you some simple advice. I suggested that
since the question you asked is very basic and that it is covered in even the
most basic books on statistics that you go to the nearest university library
and browse through BUSINESS STATISTICS texts. I find that Business Stat
books are generally more easily read and they contain many clear, practical
worked out problems and examples.
I also suggested that you learn a little more before asking your questions
and that when asking a question you indicate what you have done to try to
solve the problem. I don't think that this is a group that is in a position
to answer homework questions. I would also suggest you speak with the
instructor. Again, this is very basic stuff.
Obviously you feel you can program you hand-held computer (PalmPilot?) if you
know the formulas and I believe you can. It is really easy to do so given
the formulas you need but, without understanding how and what you are doing
when you use Z values you accomplish very little.
I have my students xerox a copy of the Z table. One sheet of paper contains
all the values you will ever need. They know how to interpolate values if
that becomes necessary.
A Z value is, in many cases, simply a way of expressing how far apart two
measurements are. The Z is based on how many standard deviations are
involved.
A simple example. The population is know to have a mean (mu) of 25 with a
standard deviation of 5. You select a random sample from this population.
The same is 50. Upon calculating the mean of this sample you come up with
27.500. The question becomes, what is the probability that this sample fo 50
with a mean of 27.500 came from a population with a mu of 25 and standard
deviation of 5.
27.500 - 25 gives a difference of 2.50. You must now determine the z value
by dividing by the standard error of the mean, which in this case is 5/square
root of 50.
The Z become 3.5355. The formula for calculating the probability value of a
Z of this size is rather complicated but should be available in many advanced
books on statistics. It is simpler to use the table of Z values to come up
with the probability.
There is more to simply programming to get this value, you must understand
one-tail and two-tail tests, null hypothesis, alternative hypothesis, simple
random sampling and why it is done, and other items.
You have just started in the field of statistical analysis. It is a very
powerful tool and, if used correctly (and understood) can be a great help to
those in the field of Psychology.
If you would like, I believe I can provide you with the computer program
which allows you to end a Z value and determine the probability associated
with that value. You may or may not decide that it is worth programming. I
think that using a single seet table is a lot less work.
Just my two cents.
GOD BLESS AMERICA
Dr. Robert C. Knodt
4949 Samish Way, #31
Bellingham, WA 98226
[EMAIL PROTECTED]
"The vocation of every man and woman is to serve other people." -- Tolstoy
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