public interface StatisticalCategoryDataset extends CategoryDataset {

    /**
     * Returns the mean value for an item.
     *
     * @param row  the row index (zero-based).
     * @param column  the column index (zero-based).
     *
     * @return The mean value.
     */
    public Number getMeanValue(int row, int column);

    /**
     * Returns the mean value for an item.
     *
     * @param rowKey  the row key.
     * @param columnKey  the columnKey.
     *
     * @return The mean value.
     */
    public Number getMeanValue(Comparable rowKey, Comparable columnKey);

    /**
     * Returns the standard deviation value for an item.
     *
     * @param row  the row index (zero-based).
     * @param column  the column index (zero-based).
     *
     * @return The standard deviation.
     */
    public Number getStdDevValue(int row, int column);

    /**
     * Returns the standard deviation value for an item.
     *
     * @param rowKey  the row key.
     * @param columnKey  the columnKey.
     *
     * @return The standard deviation.
     */
    public Number getStdDevValue(Comparable rowKey, Comparable columnKey);