tag:blogger.com,1999:blog-7464708.post7499189197007686673..comments2024-03-22T06:05:36.544-04:00Comments on Kids Prefer Cheese: Unit--root-toot-tootin'Mungowitzhttp://www.blogger.com/profile/02340064320347875601noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-7464708.post-14806864398883284512013-04-29T14:45:48.577-04:002013-04-29T14:45:48.577-04:00Maybe not an "Augmented Dickey Fuller" j...Maybe not an "Augmented Dickey Fuller" joke but check out this one about the 'null hypothesis. http://www.statisticsblog.com/2013/04/sudden-clarity-about-the-null-hypothesis/StatsJunkienoreply@blogger.comtag:blogger.com,1999:blog-7464708.post-47858743765673910552013-04-28T23:07:27.487-04:002013-04-28T23:07:27.487-04:00I wonder if this is going to go "smackdown wa...I wonder if this is going to go "smackdown watch" or "stupidest person in the world"? <br /><br />On a possibly related note, how come there aren't more "Augmented Dickey Fuller" jokes?Gerardonoreply@blogger.comtag:blogger.com,1999:blog-7464708.post-39342957215474820542013-04-28T16:13:07.749-04:002013-04-28T16:13:07.749-04:00I certainly agree real GDP per person is unlikely ...I certainly agree real GDP per person is unlikely to be I(2). But suppose it is. That's what DeLong's first two bullets assert (assuming "highly persistent" means "permanent"). Then for the 3rd bullet he says to add short-run transitory shocks to the level of real GDP per person. Finally he claims "univariate ARIMA just does not cut it as a description." But the model he has laid out is described (exactly, if there's no other serial correlation) by a univariate ARIMA: an ARIMA(0,2,2). For example, see Hyndman et al. (2008), Forecasting with Exponential Smoothing, Springer, p. 169. I guess the problem is Brad does not know much about "mean reversion" or "ARIMA." This may not be the first time ignorance hindered commentary by Brad.David O. Cushmannoreply@blogger.com