问题描述
可以说,我们正在计算考试成绩的平均值:
Lets say, we're calculating averages of test scores:
初始考试成绩:75、80、92、64、83、99、79
Starting Test Scores: 75, 80, 92, 64, 83, 99, 79
平均= 572/7 = 81.714 ...
Average = 572 / 7 = 81.714...
现在给定81.714,如果您不知道初始测试分数,是否可以添加一组新的测试分数来扩展"该平均值?
新考试成绩:66、89、71
New Test Scores: 66, 89, 71
平均= 226/3 = 75.333 ...
Average = 226 / 3 = 75.333...
正常平均值将为:798/10 = 79.8
Normal Average would be: 798 / 10 = 79.8
我尝试过:
Avg = (OldAvg + sumOfNewScores) / (numOfNewScores + 1)
(81.714 + 226) / (3 + 1) = 76.9285
Avg = (OldAvg + NewAvg) / 2
(81.714 + 79.8) / 2 = 80.77
而且都没有达到应该"的确切平均值.考虑到您不知道初始值,这样做在数学上是否可行?
And neither come up the exact average that it "should" be. Is it mathematically possible to do this considering you don't know the initial values?
推荐答案
您必须知道原始组和旧平均值中的考试分数数量:
You have to know the number of test scores in the original set and the old average:
newAve = ((oldAve*oldNumPoints) + x)/(oldNumPoints+1)
这篇关于常规-是否可以根据现有平均值并为所得平均值指定新参数来计算平均值?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!