Give an example error with the minimum number of flipped bits where the CRC cannot detect that there is an error for the above computed . You can represent the error as a binary string X of the same length as the payload concatenating CRC bits, , where a bit in X is 0 represents the corresponding bit in is not flipped, and a bit is 1 represents the corresponding bit in is flipped. Taking the XOR of X and will generate the received payload and CRC bits at the receiver (after the bit error happens). For a simpler example, assume = 10010 011 where the last 3 bits are CRC, then a bit error string X = 00110 001 (with 3 flipped bits; 3 = the number of 1s in X) will result in the receiver side receiving = 10100 010.