tests and cleanup

lib/statistics/Slope.cs

@@ -7,15 +7,37 @@ namespace QuanTAlib;
 /// The Slope class calculates the slope of a linear regression line, along with other
 /// statistical measures such as intercept, standard deviation, R-squared, and the last
 /// point on the regression line. It uses the least squares method for calculation.
+///
+/// In financial analysis, slope is important for:
+/// - Identifying trends in price movements or other financial metrics.
+/// - Measuring the rate of change in a financial time series.
+/// - Assessing the strength and direction of relationships between variables.
+/// - Supporting technical analysis indicators and trading strategies.
 /// </remarks>
 public class Slope : AbstractBase
 {
     private readonly int _period;
     private readonly CircularBuffer _buffer;
     private readonly CircularBuffer _timeBuffer;
+
+    /// <summary>
+    /// Gets the y-intercept of the regression line.
+    /// </summary>
     public double? Intercept { get; private set; }
+
+    /// <summary>
+    /// Gets the standard deviation of the y-values.
+    /// </summary>
     public double? StdDev { get; private set; }
+
+    /// <summary>
+    /// Gets the R-squared value, indicating the goodness of fit of the regression line.
+    /// </summary>
     public double? RSquared { get; private set; }
+
+    /// <summary>
+    /// Gets the y-value of the last point on the regression line.
+    /// </summary>
     public double? Line { get; private set; }
 
     /// <summary>
@@ -90,6 +112,13 @@ public class Slope : AbstractBase
     /// It also calculates and updates the Intercept, StdDev, RSquared, and Line properties.
     /// If there are fewer than 2 data points, or if the sum of squared x deviations is 0,
     /// the method returns 0 and sets the additional properties to null.
+    ///
+    /// Interpretation of results:
+    /// - Positive slope: Indicates an upward trend in the data.
+    /// - Negative slope: Indicates a downward trend in the data.
+    /// - Slope close to 0: Indicates a relatively flat or no clear trend in the data.
+    /// The magnitude of the slope represents the rate of change in the dependent variable
+    /// (y) for each unit change in the independent variable (x).
     /// </remarks>
     protected override double Calculation()
     {