Dear all;
I am an orthopedic surgery fellow at children's hospital in San Diego. I
have recently completed a large study on age and sex related changes in lung
density by CT scan and I need some statistical help. I no longer have
access to a statistician who accomplished the following in a prior project:
Statistical analysis was accomplished as follows: Age was categorized by
year and each year was transformed into its own class variable. Quantile
regression was performed using Stata 8 (College Station, TX) on each of the
quantiles shown in CDC growth charts for the 3rd, 5th, 10th, 25th, 50th,
75th, 90th, 95th, and 97th percentiles. As employed, this regression
technique fitted a line of differing slopes between each age category for
each percentile. By using each quantile's generated model, predicted values
were generated to graph a line representing each specific quantile. The
predicted values were then smoothed by fitting a line via fractional
polynomial estimation.
I have written the do files to complete the graphs for the previous
manuscript, but I have no idea how to do a quantile regression.
Is there anyone who would like to help? I have a grant and can afford a
reasonably priced statistician.
Thanks,
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
