ex-3: review

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Michele Guerini Rocco 2020-05-28 20:46:49 +02:00
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@ -388,40 +388,47 @@ Likelihood results:
----------------------------
par $p$-value
------------ ---------------
$\alpha_L$ 0.18
$α_L$ 0.18
$\beta_L$ 0.55
$β_L$ 0.55
$\gamma_L$ 0.023
$γ_L$ 0.023
----------------------------
Table: Likelihood results compatibility.
$\chi^2$ results:
---------------------------------
par $p$-value
----------------- ---------------
$\alpha_{\chi}$ 0.22
----------------------------
par $p$-value
------------ ---------------
$α_χ$ 0.22
$\beta_{\chi}$ 0.89
$β_χ$ 0.89
$\gamma_{\chi}$ 0.0001
---------------------------------
$γ_χ$ 0.0001
----------------------------
Table: $\chi^2$ results compatibility.
It can be concluded that only the third parameter, $\gamma$ is not compatible
with the expected one in both cases. An in-depth analysis of the algebraic
arrangement of $F$ would be required in order to justify this outcome.
It can be concluded that, with both methods, the parameters $\alpha$ and $\beta$
were recovered succefully, while $\gamma$ is incompatible. However, the
covariance was estimated using the Cramér-Rao bound, so the errors may be
underestimated, which must be the case for $\gamma$.
Since two different methods similarly underestimated the true value of
$\gamma$, it was suspected the Monte Carlo simulation was faulty. This
phenomenon was observed frequently when generating multiple samples, so it
can't be attributed to statistical fluctuations in that particular sample.
The issue remains unsolved as no explanation was found.
\vspace{30pt}
## Isotropic hypothesis testing
What if the probability distribution function was isotropic? Could it be
compatible with the found results?
If $F$ was isotropic, then $\alpha_I$, $\beta_I$ and $\gamma_I$ would be $1/3$
, 0, and 0 respectively, since this gives $F_I = 1/{4 \pi}$. The t-test gives a
$p$-value approximately zero for all the three parameters, meaning that there is
no compatibility at all with this hypothesis.
What if the probability distribution function were isotropic?
Is this hypothesys compatible with the observation?
If $F$ is isotropic, $\alpha_I$, $\beta_I$ and $\gamma_I$ would be $1/3$ , 0,
and 0 respectively, since this gives $F_I = 1/{4 \pi}$. The t-test gives a
$p$-value approximately zero for all the three parameters, meaning that there
is no compatibility at all with this hypothesis.