# statistics help

wakefiel at ihug.co.nz wakefiel at ihug.co.nz
Mon Nov 10 09:57:29 EST 1997

```Hi, Daniel,

I am not a statistician and neither had any formal statistical
training.  So I will not give you any advice but will let you know what
I will do.

>
> - Is it more appropriate to perform the statistical calculations on
> unmodified titer data or to use a log of the individual titers?

Depending on the test you are going to do.  If you are going to use a
parametric analysis, one condition is the data have to be continueous
and normal distribution.  Therefore, one way to normalise the data is
doing a log transformation.

> - Similarly, is it more appropriate to compare groups by arithmetic
> means of titers or geometric means? and  why?
>
> - When comparing groups of animals, what is the most appropriate
> statistical method for assessing significance?  I have used Student's
> t-test, dominance statistic and Wilcoxon-Mann-Whitney test.  It is not
> clear to me which, if any, of these techniques will yield the
> appropriate answer.  Is there another that may be more useful (and
> correct)?

Dependent of how many groups you have.  Student's T test is used for two
groups comparison with parametric data.  If you have more than two
groups, you will probably have to do an one-way analysis of variance (or
multiple).  If a significance is found then you can do pairwise
comparison test.  There are a number of tests, which one to use once
again will depend on your data, such as whether you compare all groups
with one control group? or are you interested in the difference between
different groups etc.
>
> - Can anyone suggest either references or books in which statistical
> analysis of immune responses is discussed?  I would prefer information
> sources aimed at the non-statistician.
>
> If there is anyone out there with experience in developing
> immunogenicity assays such as these and would be willing to share
> their insights, it would be most appreciated.
>
> Thank you in advance
>
> Daniel Cox,  Ph.D.
> Worcester, MA USA
>
> decox at kersur.net

I hope this is of some help.  If anyone tell you different, trust their
views.

Good luck.

Wangxue

```