This paper attempts to find out what is the role of competitive environment in shaping the sensitivity of growth in banking to the business cycle. To answer this question, we apply a large set of individual bank level data including over 8000 banks operating in more than 100 countries. This study uses the growth of assets, loans, deposits and leverage as proxies of bank growth and Lerner index as a proxy for the competitive environment. The analysis shows that decreased competition is associated with increased procyclicality of bank growth. However, in a perfectly competitive environment the growth turns out to be countercyclical. This effect differs between high- and lowincome countries. A perfectly competitive environment is associated with countercyclical growth in high-income countries. The opposite result is found for low-income countries. Our results for Central Eastern European countries show that increased competition is associated with enhanced procyclicality of growth.

In this article, gold is analyzed from an investment perspective as an asset that allows you to increase your wealth. The analysis is twofold. First, it is about examining to what extent changes in gold prices in the world markets translate into changes in the prices of shares of companies that extract gold. Second, it was checked whether there is a financial leverage effect, which in this case means that changes in the price of shares of gold mining companies are greater than changes in the price of gold itself. Methodically, the Sharpe model was used and two basic parameters of the model were estimated, i.e. the intercept (alpha), and the beta coefficient as a measure of systematic risk, for the gold market and the equity market of gold mining companies and ET Fs based on these companies.
The research carried out in accordance with the logic of the Sharpe model shows that the obtained value of the alpha parameter for the stock market was positive, while for the gold market it was negative. At the same time, higher levels of this parameter are beneficial to the investor, which means that an advantage of the stock market over the gold market exists. In turn, the estimated beta for the stock market is much lower than for the gold market. The systematic risk level for stocks is 0.45, and for the gold market it is 1.98, which is a significant difference. The stocks of gold mining companies can be classified as defensive against the stock market (the rate of return of the gold mine stock is insensitive to market movements) and aggressive against the gold market (the rate of return of the gold mine shares reacts more strongly than the movement in the price of gold).

The use of quantitative methods, including stochastic and exploratory techniques in environmental studies does not seem to be sufficient in practical aspects. There is no comprehensive analytical system dedicated to this issue, as well as research regarding this subject. The aim of this study is to present the Eco Data Miner system, its idea, construction and implementation possibility to the existing environmental information systems. The methodological emphasis was placed on the one-dimensional data quality assessment issue in terms of using the proposed QAAH1 method - using harmonic model and robust estimators beside the classical tests of outlier values with their iterative expansions. The results received demonstrate both the complementarity of proposed classical methods solution as well as the fact that they allow for extending the range of applications significantly. The practical usefulness is also highly significant due to the high effectiveness and numerical efficiency as well as simplicity of using this new tool.