एक चुने हुए प्रतिदर्श (sample) समूह में देखे गए लक्षणों के परिकलित औसत मूल्य को किस रूप में परिभाषित किया गया है?

The 'Drain of Wealth' theory was propounded by which Indian nationalist leader?

Which event is considered the turning point in Mahatma Gandhi's leadership in the Indian independence movement?

Which African leader is known for his non-violent opposition to colonial rule?