On Wed, 16 Feb 2011, stif...@gmx.de wrote:

Hey everyone,

For an investment strategy I built some portfolios of historical stock returns 
(every 6 month for 10 years->20observations). To get more observations I´m 
using overlapping observations(40obs. which means lag=1).The goal is to test 
whether the reruns are positiv or market efficient(=0).

To correct for autocorrelation I would like to use NeweyWest(sandwich)in R, to get the correct standard deviation for the t-test, but NeweyWest requires a regression model (lm or glm) which I dont have. Is there a possibility to do this without a linear model??

Use the trivial linear model lm(y ~ 1) whose only coefficient then corresponds to the estimated mean of y.

Furthermore, if I understand you correctly, you induce a strong autocorrelation by using the overlapping observations. So you may be better off modeling this explicitly in an arima() model, or maybe a gls() approach.

hth,
Z

Thanks!!! solari
--
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