Properties
Information about the Q-Q Plot is displayed in the Properties Pane or (if you select an option from the Chart toolbar) as a Summary Table on the chart itself.
| Sample Nx / Ny | The number of samples for each grade range. |
| X and Y Mean | The sum of the values divided by the total number of values, for each grade range. |
| X and Y Variance | A measure of dispersion within each grade range; the average of the squared deviations from the mean. |
| X and Y Standard Deviation | Sample standard deviation: the square root of the sample variance for each grade range. |
| Number of quantiles | The number of quantiles (or bins). |
| Correlation Coefficient | The (Pearson) Correlation Coefficient is a measure of the correlation (linear dependence) between two variables X and Y, giving a value between +1 and -1 inclusive. |
| Standard Deviation | This is the sample standard deviation of the values shown on the chart. The Standard Deviation is a measure of the spread of the data (the way in which they differ from the mean). |
| Coefficient of variation | The Coefficient of variation is a normalised measure of dispersion of a probability distribution. It is defined as the ratio of the standard deviation to the mean. |
| Rank Correlation Coefficient | The (Spearman) Rank Correlation Coefficient is a non-parametric measure of statistical dependence between two ranked variables. |
| xVar / yVar | Covariance is a measure of how much two variables change together. |
| Precision | Precision is a measure of the reproducibility of a sample result using the same process. A sample may be both inaccurate and imprecise, giving little faith in its assay value, particularly when sparse data is then used to interpolate an ore body. An accurate sample may also be imprecise, with the repeat values varying greatly whilst the average grade may still approximate the true grade. In order to calculate the precision, the mean, standard deviations and variance of the two variables, X and Y, are required, together with the correlation coefficient. . A perfect result is a zero value. A 0.1 result indicates ±10%. |