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st: functions of different subsets of data?


From   "Gustaf Rydevik" <[email protected]>
To   [email protected]
Subject   st: functions of different subsets of data?
Date   Wed, 6 Dec 2006 17:34:49 +0300

Hi all,

I'm fairly new to stata, and still get frustrated when trying to
figure out certain simple things. The major issue is the lack of
ability to create constants, and being forced to only use variables.
I'm probably missing something, but that's what it seems like to me.

Right now, I'm trying to do a primitive regression-type calculation.

I have two columns , Xi and Yi, and would like to calculate:

1) The means for the subsets  that belong to
10950(30yrs)>=agegroup>=1825 (5yrs), and 21900>=agegroup>10950,
separately and for both columns.

2) Then calculate the slope (Yi_mean2-Yi_mean1)/(Xi_mean2-Xi_mean2)

The best thing I've come up with so far is to generate temporary
variables with NA's where not defined using statements like:

gen Xi_mean1 = (sum) Xi if agegroup >=1825 & agegroup <=10950
replace Xi_mean1=Xi_mean1/6

,and then calculating 2) refering to a specific entry in the columns
of the temporary variables with subsetting. However, Because I can't
know which row number contain a real value (everything is taking place
inside a .do file), and since I'm dealing with constants,  this
roundabout way bothers me.

Is there a more "natural" way to do things?


Data is at the end of this message, tab separated.

Thanks in advance!

best

Gustaf

--

email:[email protected]
tel: +46(0)703051451
address: Kantorsgatan 50:190 75424 Uppsala Sweden
---------

agegroup	Dx	px	N_exact	N_plus	Dx_plus	Xi	Yi
"Under 1 year"	65	1941.021		54733.75	377	.0068879	
"1-4 yrs"	83	8176.678	1011.77	52792.73	312	.0059099	.0191649
"5-9 yrs"	12	9764.077	1794.075	44616.05	229	.0051327	.0402114
"10-14 yrs"	7	8335.471	1809.955	34851.97	217	.0062263	.0519326
"15-19 yrs"	13	6162.906	1449.838	26516.5	210	.0079196	.0546768
"20-24 yrs"	11	4248.53	1041.144	20353.6	197	.0096789	.0511528
"25-29 yrs"	14	3624.372	787.2902	16105.07	186	.0115492	.0488846
"30-34 yrs"	18	3009.719	663.4091	12480.7	172	.0137813	.0531548
"35-39 yrs"	17	2486.2	549.5919	9470.976	154	.0162602	.0580291
"40-44 yrs"	17	1885.127	437.1327	6984.776	137	.0196141	.0625836
"45-49 yrs"	16	1292.577	317.7704	5099.649	120	.023531	.0623122
"50-54 yrs"	14	857.0027	214.958	3807.072	104	.0273176	.0564628
"55-59 yrs"	5	647.1109	150.4114	2950.07	90	.0305078	.0509857
"60-64 yrs"	7	684.2745	133.1385	2302.959	85	.036909	.0578119
"65-69 yrs"	12	547.0876	123.1362	1618.684	78	.0481873	.0760718
"70-74 yrs"	12	383.9042	93.09918	1071.597	66	.0615903	.0868789
"75-79 yrs"	17	283.4497	66.73539	687.6925	54	.0785235	.0970425
"80-84 yrs"	11	185.6701	46.91198	404.2428	37	.0915292	.116049
"Above 85 years"	26	218.5736	40.42437	218.5727	26	.1189536	.184947
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