completion Status. QUESTION 15 In a recent issue of the IEEE Spectrum, 84 engineering conferences were announced. Four conferences lasted two days. Thirty-six lasted three days. Eighteen lasted four days. Nineteen lasted five days. Four lasted six days. One lasted seven days. One lasted eight days. One lasted nine days. Let X = the length (in days) of an engineering conference. If you were planning an engineering conference, which would you choose as the length of the conference: mean; median; or mode? O a. Mode because it shows the most common or preferred choice of attendees. O b. None of these. O c. Mean because it shows the average of the attendees choices. O d. Median because it shows the midpoint of the attendees choices