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All have the same trend, but more filtering leads to higher r 2 of fitted trend line. The least-squares fitting process produces a value, r-squared (r 2), which is 1 minus the ratio of the variance of the residuals to the variance of the dependent variable. It says what fraction of the variance of the data is explained by the fitted trend line.
In project management, trend analysis is a mathematical technique that uses historical results to predict future outcome. This is achieved by tracking variances in cost and schedule performance. In this context, it is a project management quality control tool. [4] [5]
The above equations are efficient to use if the mean of the x and y variables (¯ ¯) are known.If the means are not known at the time of calculation, it may be more efficient to use the expanded version of the ^ ^ equations.
The trend-cycle component can just be referred to as the "trend" component, even though it may contain cyclical behavior. [3] For example, a seasonal decomposition of time series by Loess (STL) [ 4 ] plot decomposes a time series into seasonal, trend and irregular components using loess and plots the components separately, whereby the cyclical ...
Linear regression was the first type of regression analysis to be studied rigorously, and to be used extensively in practical applications. [4] This is because models which depend linearly on their unknown parameters are easier to fit than models which are non-linearly related to their parameters and because the statistical properties of the ...
Sample variance of x: s 2 x: 11 exact Mean of y: 7.50 to 2 decimal places Sample variance of y: s 2 y: 4.125 ±0.003 Correlation between x and y: 0.816 to 3 decimal places Linear regression line y = 3.00 + 0.500x: to 2 and 3 decimal places, respectively Coefficient of determination of the linear regression: 0.67 to 2 decimal places
Exponential smoothing was first suggested in the statistical literature without citation to previous work by Robert Goodell Brown in 1956, [3] and then expanded by Charles C. Holt in 1957. [4] The formulation below, which is the one commonly used, is attributed to Brown and is known as "Brown’s simple exponential smoothing". [5]
In time series analysis, the moving-average model (MA model), also known as moving-average process, is a common approach for modeling univariate time series. [1] [2] The moving-average model specifies that the output variable is cross-correlated with a non-identical to itself random-variable.