[英]Chi square value from scipy.stats has degree of freedom = 0 as default. What does this mean?
Hi I have data sets (maxwellian and gaussian) that I make a histogram plot with. 嗨,我有一些数据集(麦克斯韦和高斯),可以用来做直方图。 I fit the data using scipy.stats.chisquare but it has by default, degrees of freedom as 0. If I understand correctly, it is not possible right?
我使用scipy.stats.chisquare拟合数据,但默认情况下其自由度为0。如果我理解正确,那不可能吗?
To directly answer your question, you are correct - Degrees of freedom being 0 is invalid/useless. 要直接回答您的问题,您是正确的-自由度为0无效/无用。
scipy.stats.chisquare
parameter isn't degrees of freedom but an adjustment to degrees of freedom. scipy.stats.chisquare
参数不是自由度,而是对自由度的调整。 Degrees of freedom defaults to k - 1
when ddof = 0. k
can be directly determined from the data you pass to the chisquare function. 当ddof = 0时,自由度默认为
k - 1
。可以直接根据传递给chisquare函数的数据确定k
。
From the Scipy chiqsuare documentation 从Scipy chiqsuare文档中
ddof : int, optional “Delta degrees of freedom”: adjustment to the degrees of freedom for the p-value.
ddof:int,可选的“ Delta自由度”:调整p值的自由度。 The p-value is computed using a chi-squared distribution with k - 1 - ddof degrees of freedom, where k is the number of observed frequencies.
使用具有k-1-ddof自由度的卡方分布来计算p值,其中k是观察到的频率数。 The default value of ddof is 0.
ddof的默认值为0。
ddof
is the delta not the absolute value for degrees of freedom. ddof
是增量而不是自由度的绝对值。 So degrees of freedom is k - 1 and ddof
is an adjustment subtracted from k - 1. So when ddof = 0, degrees of freedom = k - 1 - 0
or k - 1
. 因此,自由度为k-1,而
ddof
是从k-1减去的调整量。因此,当ddof = 0时,自由度= k - 1 - 0
1-0或k - 1
。 When ddof = 1, degrees of freedom = k - 1 - 1
or k - 2
. 当ddof = 1时,自由度=
k - 1 - 1
或k - 2
。 k is the number of observed frequencies and the chisquare
function can determine that from the data you pass k是观察到的频率数,
chisquare
函数可以根据您传递的数据确定
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