Hello,
Thank you Alan.
By using the 'adjust' command, I have verified that the mean is taken (i.e., by also using the sum, d command, the mean is the same).
---begin example---
. adjust
-----------------------------------------------------------------------------------------------------------------
Dependent variable: price Command: qreg
Variables left as is: weight, length, foreign
-----------------------------------------------------------------------------------------------------------------
----------------------
All | xb
----------+-----------
| 5473.59
----------------------
Key: xb = Linear Prediction
. predict test, xb
. sum test, d
Linear prediction
-------------------------------------------------------------
Percentiles Smallest
1% 948.5573 948.5573
5% 1959.794 1361.076
10% 3384.565 1920.458 Obs 74
25% 4723 1959.794 Sum of Wgt. 74
50% 5435.645 Mean 5473.588
Largest Std. Dev. 1813.017
75% 6385.588 8804.352
90% 7638.702 9254.924 Variance 3287029
95% 8804.352 9423.244 Skewness -.1285146
99% 9771.52 9771.52 Kurtosis 3.297427
---end example---
Note the mean is 5473.59, the same in the adjust and sum commands.
But I also wanted to verify that even though the commmand is qreg (for quantile regression), I should use the mean to report the statistics, and not the 50th percentile?
Thank you!
----------------------------------------
> Date: Wed, 14 Jan 2009 13:39:10 -0500
> Subject: Re: st: How to interpret and summarize adjusted medians
> From: [email protected]
> To: [email protected]
>
> You might want to look at the help file for -adjust-. Here are some examples:
>
> sysuse auto
> qreg price weight length foreign
> adjust
> adjust, by(foreign)
> adjust, by(rep78)
> adjust, by(rep78 foreign)
> adjust weight length, by(foreign)
>
> Best,
> Alan
>
>
> On Wed, Jan 14, 2009 at 1:30 PM, I M wrote:
>> Hello,
>>
>> I have a multivariate model (quantile regression, qreg) with a set of covariates.
>>
>> I have run the quantile regression model, then generated predicted values (values adjusted according to the covariates in my model).
>>
>> Essentially, these predicted values are the predicted medians.
>>
>> How do I summarize these predicted medians? i.e. if I want to report the predicted median by gender, how would I do this?
>>
>>
>>
>> ---begin example---
>> /*quantile regression model*/
>> qreg [outcome] [predictor variable 1] [predictor variable 2, i.e. gender]
>>
>> /*generate predicted medians based on estimates*/
>> predict [predicted medians], xb
>>
>> /*summarize the predicted values*/
>> sum [predicted medians], detail
>>
>> ---end example---
>>
>>
>>
>> The sum, detail command would give me the percentiles and the mean (and some other statistics).
>>
>> If I want to summarize the predicted medians, would I state the mean from the "sum" command, or would I state the median from the "sum" command?
>>
>> In other words, do I want to report the mean of the 'predicted median', or the median of the 'predicted median'?
>>
>> Thank you immensely!
>>
>> *
>> * For searches and help try:
>> * http://www.stata.com/help.cgi?search
>> * http://www.stata.com/support/statalist/faq
>> * http://www.ats.ucla.edu/stat/stata/
>>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
