Section B Concepts and definition [20 Marks] There are Seven questions in this section. Answer all questions. You are expected to spend 40 minutes on this section. 1. Dene a variable. (2 marks) 2. What is the main challenge in the operationalization of variables? (3 marks} 3. Values of categorical variables must be exhaustive and mutually-exclusive. Explain what does this mean. (4 marks) ' 4. Dene dependent and independent variables. (4 marks) 5. When is the median to be preferred to the arithmetic mean as a measure of central tendency? Why? (2 marks) 6. Describe the key differences between numerical data and nominal data. (2 marks) 7. List and explain the three desirable properties of tabular data