Lower left: joint probability distribution (in logarithmic scale to improve visibility) for the random variables ϖ and ϖ_True in the scenario of a truncated uniform volume density. The colour code is shown to the right of the lower right panel, and white marks the region where the probability is zero. Lower right: conditional probability distribution of the observed parallax for ϖ_True = 0.5. Upper left: conditional probability distribution for ϖ_True given an observed parallax ϖ. The fractional parallax uncertainty assumed for the computation of all probabilities is f = 0.2.