यह कथन किसका है: 'स्तरीकृत यादृच्छिक प्रतिचयन (Stratified random sampling) जानबूझकर किए गए चयन के पूर्वाग्रह के विरुद्ध यादृच्छिक प्रतिचयन की अनिश्चितता को संतुलित करता 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?