In this note, I consider a general class of unobserved components (UC) models and derive a relevant inequality. This inequality implies that either of the two assumptions of standard UC models, namely, a random walk trend and uncorrelated shocks, is not satisfied if the impulse response measure...

The well known Jarque-Bera (JB) test for normality uses the sample mean and sample standard deviation for estimating the population mean and population standard deviation. Instead of the sample standard deviation, Gel and Gastwirth (2008) proposed to use a robust scale estimator, known as the...