Journal of Security and Sustainability Issues

The study attempts to forecast the total costs of a company in Poland. The first stage of the research was analyzing and evaluating the time series of total costs. It detected: trends, seasonality and a random factor. This became a premise for the application of two methods for forecasting: Holt-Winters’ multiplicative and additive. The research shows that the Holt-Winters’ multiplicative model proved to be better in forecasting total costs in the research subject. The forecasted total costs from July to December 2022 will reach PLN 45 395 685, while from January to December 2023, their value will amount to PLN 85 948 927.

The study presents a multidimensional comparative analysis of two dependent variables: the number of passengers transported by air in 28 European countries and the price of one barrel of crude oil in dollars. The conducted analysis shows that in the historical data concerning the identical periods (months) in both tested series, dependencies can be found. This allowed for the construction of a zero-one multiple regression model in order to confirm the impact of the number of passengers travelling by air on the price of one barrel of crude oil and describe this phenomenon with an analytical function.

The multidimensional comparative analysis and the forecasting of minimum salaries in 21 European countries were conducted in the study. The research began with the ranking of the data, the amount of salary rates taken as a basis, the rise expressed in euro and the values of dynamics indices on a constant base. Then the data was aggregated. The time series of the lowest salaries in 21 European countries was analyzed and evaluated. Thus, regularities were observed that were used to select the Holt-Winters’ exponential smoothing method for the forecasting of these salaries. The obtained forecasts were analyzed and evaluated with the use of indices, such as forecasting errors.

The article presents a multidimensional comparative analysis of the impact of crude oil and liquefied petroleum gasses (LPG) prices on the housing price index in 28 European countries. Research shows that the COVID-19 pandemic and the attack of Russia on Ukraine have led to similar large fluctuations in crude oil and LPG prices. This, in turn, contributed to an increase in inflation and house price indices in the 28 analyzed European countries. Such an increase was driven by higher total construction costs, including higher prices for materials, energy and charges for building services. Housing prices in respective European countries vary. The study examines the dynamics of their changes and compares them with the use of ranking.

The article presents a multidimensional comparative analysis of the number of employees in the enterprise sector in Poland on a quarterly basis between 2010-2021 and new and withdrawn jobs dynamically in terms of economic security. The volume of employment and salary for work in Poland in the enterprise sector by type of activity was analyzed. The last stage of the research was the analysis and evaluation of the time series of salaries in Poland and its forecasting for the future.