The simulation of an experiment on looking for sterile neutrinos at a nuclear reactor at short distances is presented. It has been shown that statistical fluctuations in experimental bins always imitate the oscillatory behavior of the spectrum. An amplitude of the detectable oscillations decreases when statistics grows up in case of oscillations absence, while mass parameter tends to be accidental. When we simulate spectra in a detector with oscillations the parameters found in fitting become close to parameters applied to spectra starting from statistics 10$^5$ events in near detector.