1. A method of analyzing respiratory rate monitoring parameters to determine confidence in a measured respiratory rate, the method comprising: obtaining, with a processor, a first respiratory rate measurement from a patient from an acoustic respiratory signal; obtaining, with the processor, a second respiratory rate measurement from the patient from at least one non-acoustic physiological signal; calculating, with the processor, a confidence associated with the first respiratory rate measurement based at least on a comparison between the first and second respiratory rate measurements and reflecting a degree to which the first and second respiratory rate measurements correspond to each other, wherein said calculating comprises calculating a relatively higher confidence when the first and second respiratory rate measurements have a relatively higher degree of correspondence to each other and a relatively lower confidence when the first and second respiratory rate measurements have a relatively lower degree of correspondence to each other; and displaying, with a display, safety zones together with a visual confidence indicator responsive to the confidence, the visual confidence indicator comprising a probability distribution having a peak corresponding to at least one of the first and second respiratory rate measurements and a distribution dispersion depending at least on the confidence, wherein a visual position of the visual confidence indicator with respect to the safety zones reflects a degree of safety risk to the patient.