Abstract: A method and a device for determining a statistical parameter for all frequencies of a frequency distribution of signal levels of a test signal registered respectively in several observation intervals counts the frequency of the signal level of the test signal measured in each case within the respective signal-level range and at the respective value of the time or frequency raster of the frequency distribution from new within every observation interval, and buffers it for display on a display device. After every observation interval, for every signal-level range and every value of the time or frequency raster of the frequency distribution, the respective statistical parameter from the respective, newly-buffered frequency and all respective frequencies measured and buffered at earlier observation intervals is determined and buffered.