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© July 13, 2014 Lorentz JÄNTSCHI |
Generalized Grubbs test on moments of order 1 (G1)
Let's consier a series of observed cummulative frequencies fi obtained testing an known distribution function against a series of n data points (like in the following example).(n = 4; (xi)i=1,2,3,4 = Sort{Random[Normal(0,1)]}; fi = CDF(xi; Normal(0,1))
i xi fi 1 -1.310 0.095 2 -1.029 0.152 3 -0.793 0.214 4 +2.052 0.980
Let's consider only \[ g0 \gets \mathop{\max}\limits_{1 \leq i \leq n} |f_i-0.5| \] It's associated probability (to be observed, CDF) is (see (Jäntschi, 2019)):\[ p(g0) \gets \left( 2 \cdot g0 \right) ^{n} \] The risk of being in error assuming that (fi)i=1, ..., n is coming from uniform distribution(the risk of being in error assuming that (xi)i=1, ..., n is coming from assumed distribution) is 1 - p.
For the above given example, g0 = 0.4799, p(g0) = 0.85, 1 - p = 15%.
Let's consider now \[ g1 = \mathop{\max} \left( \frac{|f_1 - 0.5|}{\sum_{i=1}^{n}{|f_i-0.5|}},\frac{|f_n-0.5|}{\sum_{i=1}^{n}{|f_i-0.5|}} \right) \] It's associated probability (to be observed, CDF) is to be taken from (see (Jäntschi, 2020)):
\[ p(g1) = 1 - \sum_{k=0}^{\lfloor n - \frac{1}{g1} \rfloor} (-1)^{k} \frac{(n - \frac{1}{g1} - k)^{n-1}}{k!(n-1-k)!} \]For the above given example, g1 = 0.3159, 1/g1 = 3.1655, p(g1) = 1 - 0.097, 1 - p = 9.7%.
Refs:Last Update: August 10, 2023.
- Lorentz JÄNTSCHI, 2019. A test detecting the outliers for continuous distributions based on the cumulative distribution function of the data being tested. Symmetry 11(6): 835. DOI 10.3390/sym11060835. (15p. + 7p. supp. mat.)
- Lorentz JÄNTSCHI, 2020. Detecting extreme values with order statistics in samples from continuous distributions. Mathematics 8(2): 216. DOI 10.3390/math8020216. (21p. + 21p. supp. mat.)