# st: Re: fpower

 From "Martin Weiss" To Subject st: Re: fpower Date Sat, 20 Jun 2009 22:51:15 +0200

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Seems from the explanations at http://www.ats.ucla.edu/stat/stata/dae/fpower.htm that these values are mere educated guesses, not results of calculations...
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HTH
Martin
_______________________
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----- Original Message ----- From: "CHIDLOW Agnieszka" <A.Chidlow@staffs.ac.uk>
```To: <statalist@hsphsun2.harvard.edu>
Sent: Saturday, June 20, 2009 10:36 PM
Subject: st: fpower

```
```Dear Statalisters,

```
Please forgive me if you find this request silly (or basic), but I have been having some nightmares to figure out how to use ex post "fpower" for anova. I have read about the power analysis (e.g. papers, and on www.ats.ucla.edu), but it looks like I can't do the test because I don't seem to know how to calculate delta and/or means for my groups. Hence would really appreciate some help from you.
```
My anova results are:

.anova nm year
```
Number of obs = 95 R-squared = 0.0497 Root MSE = .487822 Adj R-squared = -0.0387 Source | Partial SS df MS F Prob > F
```             -----------+----------------------------------------------------
```
Model | 1.07136314 8 .133920392 0.56 0.8055
```                        |
```
year | 1.07136314 8 .133920392 0.56 0.8055
```                        |
Residual |   20.465479    86  .237970686
-----------+----------------------------------------------------
Total |  21.5368421    94  .229115342

where: nm = 2 groups
year = 8 groups

Aggie

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• References:
• st: fpower
• From: "CHIDLOW Agnieszka" <A.Chidlow@staffs.ac.uk>