p-value; adjust p-value; calculate p-trend

[mrudula reddy pachika]

Hi,

I have data on waist circumfrence that is divided into quartiles and we are measuring a variable called e' for each of these quartiles(described in the table below)  I need help in STATA-

1. To calculate p-value for this variable (e') that is divided into quartiles and  then

2. adjust for various other variables like age, sex, race, baseline SBP, DBP, HR, prior h/o DM, trial, treatment assignment, change in SBP, and E’

3. I also need to calculate p-trend

Thanks for your help.

Gopi

waist circumfrence quartiles 

-------------------------------------------------------------------------------------- -----------------------------------------

              <26.6       26.6-29.9        29.9-33.9           >33.9          P for trend       Adj. P value

--------------------------------------------------------------------------------------    ---------------------------------------

Mean E’  7.3±1.1      7.6±1.2,           7.6±1.5           7.5±1.20

Thank you,

Gopi

[eric.a.booth]

I suspect that you haven't received a reply to this posting (here or
at TalkStats) because your question is not very clear.

Telling us that you've binned the waist variable doesn't help us get
to any of your 3 questions. In what context do you want to calculate a
p-value - what does "adjust by" these various variables mean?
Maybe show us a snippet of your data and tell us how and by what
variables you want to calculate the p-value (ttest, chi2,
regression, ?).
If your trying to calculate some kind of linear trend, why did you bin
your waist variable? Which leads me to ask: What is a p-trend ? Is
it the trend in change in the p-values you are trying to obtain across
some unit or across time; or does it refer to a chi-square statistic
for the trend (regression) of your pvar on some other, where the pvar
is the proportion rvar/(rvar+nrvar). If it's the latter, type:

ssc install ptrend, replace
help ptrend

into your command line to see a user package that does this. If your
not sure, sometimes it's helpful to at least provide the reference of
where you heard about a p-trend (e.g., I'd like to calculate a p-trend
in the same way as this article:
O'Connor, et al. 1999. "Multivariate prediction of in-hospital
mortality after percutaneous coronary interventions in 1994-1996." J
Am Coll Cardiol. 1999 Sep;34(3):681-91. )


- Eric
____
ebo...@ppri.tamu.edu
eric.a...@gmail.com

On Oct 5, 9:59 pm, mrudula reddy pachika <pachikare...@gmail.com>
wrote: