← All parts of this equation

Equation 1 · Part 6 · One Tree: The Statistics of Common Descent

=

K=P(D∣MUCA)P(D∣MIO)K = \frac{P(D \mid M_{\text{UCA}})}{P(D \mid M_{\text{IO}})}
=

What this part means

The expressions on both sides represent the same quantity under the stated assumptions.

Its job in the formula

The equals sign connects the complete expression on the left with the complete expression on the right. Both sides must have compatible units.

The passage around this formula

The logic of that adjudication reduces to one ratio. For sequence data compared under a universal-common-ancestry model against an independent-origins model, K=P(D∣MUCA)P(D∣MIO)K = \frac{P(D \mid M_{\text{UCA}})}{P(D \mid M_{\text{IO}})}. and K , the Bayes factor, states exactly how many times more probable the observed data D are under one model than the other - not a correlation coefficient, not a subjective sense of resemblance, but a single number with a precise probabilistic meaning that can in principle come out favouring either model. For the proteins Theobald examined, it was not close. Universal common ancestry came out favoured over the closest competing multiple-ancestry hypothesis by odds reported on the order of ten to the power of two…

Read this part in the article →

Learn the underlying idea

An equals sign says that the expression on its left and the expression on its right have the same value under the stated definitions and assumptions.

Open the illustrated equality: what the equals sign claims guide →

Sources cited in the surrounding passage

These citations provide research context; check each source for the exact claim it supports.