/** * Calculates the population variance for a set of data. * @since 7.4.0 */Ext.define('Ext.data.summary.VarianceP', { extend: 'Ext.data.summary.Variance', alias: 'data.summary.variancep', /** * Name of the summary function that appears in the {@link Ext.grid.plugin.Summaries} plugin */ text: 'VarP', calculate: function(records, property, root, begin, end) { var n = end - begin, avg = this.avg.calculate(records, property, root, begin, end), total = 0, i, v, ret; if (avg != null && avg !== 0) { for (i = 0; i < n; ++i) { v = this.extractValue(records[begin + i], property, root); total += Math.pow(Ext.Number.from(v, 0) - avg, 2); } } if (total !== 0 && n > 1) { ret = total / n; } return ret; }});