Probability And Statistics - Study Mode
[#91] For each element in a set of size 2n, an unbiased coin is tossed. All the 2n coin tossed are independent. An element is chosen if the corresponding coin toss were head. The probability that exactly n elements are chosen is
Correct Answer
(A) [frac{{left( {x08egin{array}{*{20}{c}}
{2{ ext{n}}} \
{ ext{n}}
end{array}}
ight)}}{{{4^{ ext{n}}}}}]
[#92] From a pack of regular playing cards, two cards are drawn at random. What is the probability that both cards will be Kings, if first card in NOT replaced?
Correct Answer
(D) $$frac{1}{{221}}$$
[#93] A fair coin is tossed n times. The probability that the difference between the number of heads and tails is (n - 3) is
Correct Answer
(B) 0
[#94] A fair coin is tossed till a head appears for the first time. The probability that the number of required tosses is odd, is
Correct Answer
(C) $$frac{2}{3}$$
[#95] Let f(x) be the continuous probability density function of a random variable X. The probability that a < X ≤ b, is
Correct Answer
(C) $$intlimits_{ ext{a}}^{ ext{b}} {{ ext{f}}left( { ext{x}}
ight){ ext{dx}}} $$