This article deals with the issues of different theoretical approaches to education. Education is seen as a tool, how to distinct different marginal productivities of employees. We start from the fact of an information asymmetry on the labour markets, asymmetry between employers and potential...

Estimation of volatility of financial time series plays a crucial role in pricing derivatives. Volatility is often estimated from historical data; however, it is well known that volatility varies in time. We propose a method to choose a suitable length of historical data to estimate contemporary...