3 ms·
Underlying: https://www.sciencedirect.com/science/article/pii/S1674987121001092?via%3Dihub https://www.sciencedirect.com/science/article/pii/S167498712...
by wrycoder 5y ago
Underlying:
https://www.sciencedirect.com/science/article/pii/S1674987121001092?via%3Dihub https://www.sciencedirect.com/science/article/pii/S167498712...
- chris_va 5y agoSection 3.3 there, the Fourier analysis, looks really weak. If you just plot 89 random numbers between 0 to 270 it'll have strong spectral peaks. Their method: > After permuting the order of the intervals, a new time series was re-calculated based on the new set of intervals. This method ensures that the test time series are between 0 and 260 Ma and the number of events remains at 89. Ultimately, only ~ 4% of the test datasets produced a higher spectral power at 27.5 Myr, indicating a confidence level of at least 96% for that period. ... seems very fishy to me. I could believe that the spectral power at that frequency is the mode in the data. I don't see a proof that the particular spectral power associated with 27.5 is statistically significant given a random set of events.
- dzdt 5y agoIt is incorrect to take 27.5 Myr as a prior fixed quantity when there was no prior theoretical reason to expect that period. Correct analysis would ask, given a randomly generated data set, what are the odds as strong a signal as this is generated for any recurring period in some range (like 3Myr-100Myr)