Probability And Statistics - Study Mode

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[#61] Let P(E) denote the probability of the event E. Given P(A) = 1, P(B) = $$frac{1}{2}$$, the values of $${ ext{P}}left( {frac{{ ext{A}}}{{ ext{B}}}}
ight)$$ xa0and $${ ext{P}}left( {frac{{ ext{B}}}{{ ext{A}}}}
ight)$$ xa0respectively are

(A) $$frac{1}{4},,frac{1}{2}$$

(B) $$frac{1}{2},,frac{1}{4}$$

(C) $$frac{1}{2}$$, 1

(D) 1, $$frac{1}{2}$$

Correct Answer

(D) 1, $$frac{1}{2}$$

[#62] An examination consists of two papers, Paper 1 and Paper 2. The probability of failing in Paper 1 is 0.3 and that in Paper 2 is 0.2. Given that a student has failed in Paper 2, the probability of failing in Paper 1 is 0.6. The probability of a student failing in both the papers is

(A) 0.5

(B) 0.18

(C) 0.12

(D) 0.06

Correct Answer

(C) 0.12

[#63] The probability of obtaining at least two "SIX" in throwing a fair dice 4 times is

(A) $$frac{{425}}{{432}}$$

(B) $$frac{{19}}{{144}}$$

(C) $$frac{{13}}{{144}}$$

(D) $$frac{{125}}{{432}}$$

Correct Answer

(B) $$frac{{19}}{{144}}$$

[#64] A lot has 10% defective items. Ten items are chosen randomly from this lot. The probability that exactly 2 of the chosen items are defective is

(A) 0.0036

(B) 0.1937

(C) 0.2234

(D) 0.3874

Correct Answer

(B) 0.1937

[#65] Consider a company that assembles computers. The probability of a faulty assembly of any computer is p. The company therefore subjects each computer to a testing process. This testing process gives the correct result for any computer with a probability of q. What is the probability of a computer being declared faulty?

(A) pq + (1 - p) (1 - q)

(B) (1 - q)p

(C) (1 - p)q

(D) pq

Correct Answer

(A) pq + (1 - p) (1 - q)