This invention relates to a method capable of calculating blood pressure variance. The method is executed by a variance calculation module. During calculation, the method includes: measuring the blood pressure of a user by utilizing a detection part to obtain a plurality of measured samples, and counting the number of the measured samples according to the measurement times； then, performing calculation according to the measured samples and the number of the samples to generate a sample mean； next, calculating a difference between each measured sample and the sample mean to generate a plurality of sample mean differences； then, calculating the sum of square of the sample mean differences to generate a total sample value； and finally, reading the total sample value and the number of the samples by utilizing an output part, and performing calculation to generate the blood pressure variance. Therefore, the dispersion degree is investigated according to the randomly-varying blood pressure value of the same person to conclude effective data and eliminate deviation data, so that the significance and benefit of blood pressure data to clinic are further improved.本發明為有關一種可算出血壓變異數之方法，其係以一變異數演算模組執行，計算時乃利用檢測部對一使用者進行血壓量測，以取得複數量測樣本，並根據量測次數，統計出該些量測樣本之樣本數，再根據該些量測樣本及該樣本數，計算產生一樣本平均值，接著計算各該量測樣本與該樣本平均值之差值，而產生複數樣本均差值，再由計算該些樣本均差值的平方和，而產生一樣本總合值，最後利用輸出部讀取該樣本總合值及該樣本數，而計算產生一血壓變異數。藉此，根據同一人隨機變量的血壓值，探討其離散程度，而歸納有效數據、剔除偏差數據，進一步提升血壓數據對臨床的意義與助益。
