Obviously you need to reshape your data into another form so that it
includes 452 observations, and then run nptrend command.
Yongfei
-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Paul O'Brien
Sent: Monday, November 11, 2002 11:36 AM
To: [email protected]
Subject: st: NPTREND problem
I have not been able to get the table layout right to do a test for trend
(NPTREND) with the following data:
WEIGHT EE20mcg EE30mcg
gained 48 24
stable 210 114
lost 38 18
What I get is this:
. tabi 48 24\210 114\38 18
| col
row | 1 2 | Total
-----------+----------------------+----------
1 | 48 24 | 72
2 | 210 114 | 324
3 | 38 18 | 56
-----------+----------------------+----------
Total | 296 156 | 452
Pearson chi2(2) = 0.2483 Pr = 0.883
. list
row col pop
1. 1 1 48
2. 1 2 24
3. 2 1 210
4. 2 2 114
5. 3 1 38
6. 3 2 18
. nptrend row, by(col)
col score obs sum of ranks
1 1 3 10.5
2 2 3 10.5
z = 0.00
Prob > |z| = 1.00
The correct answer is:
One sided P = .2965
Two sided P = .593
Where am I going wrong?
Thanks
Paul
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