## STATISTICS GLOSSARY

### Summary of Key Terms

Confidence interval - the mean of an estimate plus and minus the variation in that estimate.

Box-Jenkins - a model to forecast a variety of anticipated data points or data ranges including business data and future security prices.

Differencing - method of taking out fluctuations in a data series by subtracting the second data point from the first and the third from the second and so on.

Exponential smoothing - method of transforming time series data for a better fit by creating a weighted average.

Fourier analysis - showing complex or noisy data as a series of trigonometric or exponential functions such as sine waves.

Iterative - repeating calculations on the same data to find the best fit.

Lag - a receiver that displays a plot of power versus frequency.

Least squares - a basic method to calculate a regression line that is the sum of the squared errors is smaller than any other striaght line model.

Moving average - a method of using the average of past data to give new data forcasts.

Regression - the result of an approximation involving one or more independant variables.

Residuals - the difference from sutracting the forcast or fitted values from the actual values.

Spectral analysis - showing a set of sequenced data in the form of waves or oscillations.

Variable - a number whose value may change in an equation or similar according to its practical use.

Variance - the degree of spread in a data set obtained by taking the average of the squared deviations from the mean.

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