Actually nobody says that you can't use median. Scrum just shows way to drive the proces but you can bend it (improve it) to your needs and understanding.
If you want a statistically significant method to calculate velocity, you might try using the average and standard deviation. This way, you will be able to predict with whichever degree of certainty you are required what your velocity is.
If you wish, you can limit the data to the last few sprints, if you notice a change in the trend, and can explain it as valid.
This goes towards the Agile values of communication and courage (for the stakeholders to accept the uncertainty of the prediction).
e.g.
Team: Based on the last 5 sprints, we are 90% certain that we will be able to deliver at least 30 SP in the next sprint.
scrum doens't use average or median, it's a particular team that will choose one over the other depending upon the sophistication they want..
I will suggest if outliers are the problem then choose something like average of last 7 to 9 iterations... so once you are in lets say 15th iteration you won't be having any effect of early 'bad' iterations... .
I've found measures such as average sprint velocity (or median in your case) to be a very poor way to determine what the next sprint velocity may be. The main problem is that the formula is driving the decision making and this allows a team and SM to substitute that for real thinking.
The best way to compute next-sprint velocity that I've found (using Scrum for almost 5 years) is the following:
In the first sprint or two, it's just an educated guess. We make a guess then drop back from that a bit to ensure we don't overshoot.
If the team has picked up, say 5 extra pts in the prior sprint, increase the velocity by no more than 5 points. If the team didn't pick up any new points, keep the velocity where it is unless they struggled. If they struggled, back off a bit, say, 10%.
If the sprint failed, regroup and figure out whether it was because the team picked too much work. If so, work out what stories were actually done 100% - this total of points is your new velocity for the next sprint.
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实际上没有人说你不能使用中位数。 Scrum 只是展示了驱动流程的方法，但您可以根据您的需求和理解来调整（改进）它。
Actually nobody says that you can't use median. Scrum just shows way to drive the proces but you can bend it (improve it) to your needs and understanding.
如果您想要一种具有统计显着性的方法来计算速度，您可以尝试使用平均值和标准差。这样，您将能够以所需的确定程度来预测您的速度。
如果您愿意，您可以将数据限制为最后几个冲刺，如果您注意到趋势发生变化，并且可以将其解释为有效。
这符合沟通和勇气的敏捷价值观（让利益相关者接受预测的不确定性）。
例如
团队：根据过去 5 个冲刺，我们有 90% 的把握在下一个冲刺中能够交付至少 30 SP。
If you want a statistically significant method to calculate velocity, you might try using the average and standard deviation. This way, you will be able to predict with whichever degree of certainty you are required what your velocity is.
If you wish, you can limit the data to the last few sprints, if you notice a change in the trend, and can explain it as valid.
This goes towards the Agile values of communication and courage (for the stakeholders to accept the uncertainty of the prediction).
e.g.
Team: Based on the last 5 sprints, we are 90% certain that we will be able to deliver at least 30 SP in the next sprint.
scrum 不使用平均值或中位数，而是一个特定的团队会根据他们想要的复杂程度来选择其中之一。
我会建议，如果异常值是问题所在，那么选择类似最近 7 到 9 次迭代的平均值之类的东西...因此，一旦进入第 15 次迭代，您将不会受到早期“不良”迭代的任何影响......
scrum doens't use average or median, it's a particular team that will choose one over the other depending upon the sophistication they want..
I will suggest if outliers are the problem then choose something like average of last 7 to 9 iterations... so once you are in lets say 15th iteration you won't be having any effect of early 'bad' iterations... .
我发现平均冲刺速度（或您的情况中的中位数）等指标是确定下一个冲刺速度的非常糟糕的方法。主要问题是公式正在驱动决策，这使得团队和 SM 可以用它来代替真实的思考。
我发现（使用 Scrum 近 5 年）计算下一个冲刺速度的最佳方法如下：
在第一个或两个冲刺中，这只是一个有根据的猜测。我们先进行猜测，然后稍微回退一下，以确保我们不会过度调整。
如果团队在之前的冲刺中获得了额外的 5 分，则将速度增加不超过 5 分。如果球队没有获得任何新分数，则保持现有速度，除非他们陷入困境。如果他们遇到困难，就稍微退一步，比如 10%。
如果冲刺失败，重新组合并弄清楚是否是因为团队选择了太多工作。如果是这样，请找出哪些故事实际上已 100% 完成 - 总分就是您下一个冲刺的新速度。
I've found measures such as average sprint velocity (or median in your case) to be a very poor way to determine what the next sprint velocity may be. The main problem is that the formula is driving the decision making and this allows a team and SM to substitute that for real thinking.
The best way to compute next-sprint velocity that I've found (using Scrum for almost 5 years) is the following:
In the first sprint or two, it's just an educated guess. We make a guess then drop back from that a bit to ensure we don't overshoot.
If the team has picked up, say 5 extra pts in the prior sprint, increase the velocity by no more than 5 points. If the team didn't pick up any new points, keep the velocity where it is unless they struggled. If they struggled, back off a bit, say, 10%.
If the sprint failed, regroup and figure out whether it was because the team picked too much work. If so, work out what stories were actually done 100% - this total of points is your new velocity for the next sprint.