You are a project supervisor with SDR, Inc., a data analysis and consulting firm based in Atlanta. You are supervising the data preparation process for a large survey conducted for a leading manufacturer of paper towels. The data are being collected via in-home personal interviews and 1,823 questionnaires have been returned from the field. In cleaning the data, you find that 289 questionnaires have missing responses. The data analyst preparing the data (a student in your class), not knowing how to deal with these missing responses, approaches you for help and instructions. Please explain to the data analyst how the missing responses should be handled.