LIGO Document T1500597-v1

Quoting parameter-estimation results

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T - Technical notes
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Measuring the properties of a gravitational-wave signal is a question of parameter estimation. The end result of these studies is a set of samples drawn from the posterior probability distribution. The posterior contains all the information that we have, but may not be easily digestible; in many cases, it is desirable to quote summary statistics to concisely describe findings. In most practical cases, it is impossible to compress a complete description of a distribution down to a single number; therefore, any point estimate could miss key pieces of information. Here, we discuss various possibilities for summary statistics. We also include a discussion of how to quote systematic errors on parameter estimates. While there is no perfect answer, our suggestion is to use $X^{+Y}_{-Z}$, where $X$ is the median $Y$ and $Z$ are estimates for the statistical error (measurement precision) from the bounds of a symmetric credible interval, and then add in estimates for systematic error from the range of $X$, $Y$ and $Z$, which could be presented as $X^{+Y\pm y}_{-Z\pm z}$ or $(X\pm x)^{+Y\pm y}_{-Z\pm z}$.
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Files in CBC SVN under /pe/papers/pointEstimatesTechNote/

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