Q.3
Agricultural Statistics- ICAR JRF/SRF 2024 (Q.32)
MCQ (Single Correct) +4 −1

If the events $A_1, A_2, \dots, A_n$ are independent and $P(A_i) = \frac{1}{1+i}$ for $1 \le i \le n$, then the probability that none of these $n$ events occurs is:

1. $\frac{1}{n+1}$
2. $\frac{n-1}{n+1}$
3. $\frac{n}{n+1}$
4. $1 - \frac{1}{n+1}$
  • Probability of Non-occurrence of Independent Events:
  • Given $n$ mutually independent events $A_1, A_2, \dots, A_n$ with probabilities:
$$P(A_i) = \frac{1}{i + 1}, \quad \text{for } 1 \le i \le n$$
  • The complementary probability that event $A_i$ does not occur is:
$$P(A_i^c) = 1 - P(A_i) = 1 - \frac{1}{i + 1} = \frac{i}{i + 1}$$
  • By independence of the events, the complements $A_1^c, A_2^c, \dots, A_n^c$ are also independent:
$$P\left(\bigcap_{i=1}^n A_i^c\right) = \prod_{i=1}^n P(A_i^c) = \prod_{i=1}^n \frac{i}{i + 1}$$
  • Expanding the telescoping product:
$$P(\text{none occurs}) = \left(\frac{1}{2}\right) \times \left(\frac{2}{3}\right) \times \left(\frac{3}{4}\right) \times \dots \times \left(\frac{n-1}{n}\right) \times \left(\frac{n}{n + 1}\right)$$
  • All intermediate numerator and denominator terms cancel out, leaving:
$$P(\text{none occurs}) = \frac{1}{n + 1}$$
  • Conclusion: The probability that none of the $n$ events occurs is $\frac{1}{n+1}$ (Option 1).

Correct option: (1) Option 1

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report
Want to practice this paper in exam conditions? क्या आप परीक्षा जैसे माहौल में अभ्यास करना चाहते हैं? Test yourself in 5-question batch format with timer and hidden answers. 5-प्रश्नों के बैच फॉर्मैट, टाइमर और छिपे उत्तरों के साथ खुद को परखें।
Start Practice Mode → प्रैक्टिस टेस्ट मोड शुरू करें →

Agricultural Statistics विषय एवं अध्याय

विषय एवं पाठ्यक्रम के अनुसार सभी अध्याय देखें

Official PYQ Papers

Previous Year Papers of Agricultural Statistics

Practice official shift-wise question papers with answer keys and detailed explanations on the actual exam pattern.

1
Total Available Previous Papers

Choose Exam

Exam Directory

Browse official Previous papers and mock tests

10 Major Agriculture Exams Available