What are Mean, Median and Mode? Explain the relationship between these three measures of central tendency. (UPSC 2017, 15 Marks, )

मीन, मीडियन और मोड क्या हैं? केंद्रीय प्रवृत्ति के इन तीन मापों के बीच संबंध को समझाइए। (What are Mean, Median and Mode? Explain the relationship between these three measures of central tendency.)