can you help me understand how to answer this

0.5 (a) Let the expected value of a random variable, X , be denoted by mx. Provide technical definitions of both phrases in italics, and fully specify the role Of mx in inference of X. [30 %] (b) An uncertain voltage level is uniformly quantized, either via truncation or rounding. Stating reasonable assumptions, show that the signaltoquantizationnoise ratio at the output of the quantizer is 6 dB lower under truncation than under rounding. [35 %]