This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
Two variables can be plotted together in - 
Select and explain. 
A. Pie cha, B. Histogram, C. Frequency polygon, D. Scatter diagram
D: Scatter diagram
Answer: D: Scatter diagram 
Explanation: - scatter maps show the relationship between two variables - if dots cluster round a straight line, it shows evidence of relationship of a linear nature. If there is no such cluster, it is probable that there is no relationship between the variables. Reference : Park's textbook of preventive and social medicine, 23rd edition, pg no:847