The above waveform graph shows the impulse response of the system. The impulse response is computed with the correlation analysis method. From the impulse response of the system, you get some idea about the delay of the system. The first three points of the impulse response are insignificant, which indicates the delay of the system is equal to 3 samples. The yellow strip in the graph indicates the confidence region. The points reside in the confidence region are insignificant.