EASY

Earn 100

Let $X$ and $Y$ be two random variables such that $X + Y = 100$ . If $X$ follows Binomial distribution with parameters $n = 100$ and $p = \frac{4}{5}$ , what is the variance of $Y$ ?

50% studentsanswered this correctly

Important Questions on Probability

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Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

In a binomial distribution, mean is

18

and variance is

12

then probability of success

(p) = . . . .

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Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

A die is thrown four times. The probability of getting perfect square in at least one throw is

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Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

Let a random variable

X

has a binomial distribution with mean

8

and variance 4. If

P (X \leq 2) = \frac{k}{2^{16}},

then the value of

k

is equal to

MEDIUM

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

The probability of a man hitting a target is

\frac{1}{10} .

The least number of shots required, so that the probability of his hitting the target at least once is greater than

\frac{1}{4},

is....

HARD

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

X ~ B (n, p)

with

n = 10, p = 0.4

then

E (X^{2}) =

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Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

The probability of guessing correctly at least

8

out of

10

answers on a true-false type examination is

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Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

For an initial screening of an admission test, a candidate is given fifty problems to solve. If the probability that the candidate can solve any problem is

\frac{4}{5},

then the probability that he is unable to solve less than two problems is

MEDIUM

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

A die is thrown

7

times. What is the probability that an even number turns up at least

4

times?

MEDIUM

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

For the following distribution function $F (x)$ of a random variable $X$

$x$	$1$	$2$	$3$	$4$	$5$	$6$
$F (x)$	$0.2$	$0.37$	$0.48$	$0.62$	$0.85$	$1$

$P (3 < X \leq 5) =$

HARD

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

An experiment succeeds twice as often as it fails. The probability of at least

5

successes in the six trials of this experiment is

HARD

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

Four fair dice are thrown independently 27 times. Then the expected number of times, at least two dice show up a three or a five, is

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Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

If the mean and the variance of a binomial variate

X

are

2 & 1

respectively, then the probability that

X

takes a value greater than or equal to one is:

HARD

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

In a bombing attack, there is

50 %

chance that a bomb will hit the target. At least two independent hits are required to destroy the target completely. Then the minimum number of bombs, that must be dropped to ensure that there is at least

99 %

chance of completely destroying the target, is

. . . . .

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Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

In a workshop, there are five machines and the probability of any one of them to be out of service on a day is

\frac{1}{4}

. If the probability that at most two machines will be out of service on the same day is

{(\frac{3}{4})}^{3} k,

then

k

is equal to

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Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

Let

C_{1}

and

C_{2}

be two biased coins such that the probabilities of getting head in a single toss are

\frac{2}{3}

and

\frac{1}{3}

, respectively. Suppose

α

is the number of heads that appear when

C_{1}

is tossed twice, independently, and suppose

β

is the number of heads that appear when

C_{2}

is tossed twice, independently. Then the probability that the roots of the quadratic polynomial

x^{2} - α x + β

are real and equal, is

HARD

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

A coin is tossed

7

times. Each time a man calls head. The probability that he wins the toss at least four times is

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Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

The sum of mean and variance of a Binomial distribution

(\vec{B D})

for

3

trials is

2.7

, then the binomial distribution

\vec{B D}

is given by

HARD

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

The minimum number of times one has to toss a fair coin so that the probability of observing at least one head is at least

90 %

is:

MEDIUM

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

A shooter can hit a given target with probability

\frac{1}{4} .

She keeps firing a bullet at the target until she hits it successfully three times, and then she stops firing. The probability that she fires exactly six bullets lies in the interval

EASY

Mathematics>Statistics and Probability>Probability>Bernoulli Trials and Binomial Distribution

The mean and variance of a random variable

X

in binomial distribution are

4

and

2

respectively, then

P (X = 1)

Let X and Y be two random variables such that X+Y=100. If X follows Binomial distribution with parameters n=100 and p=45, what is the variance of Y?

Important Questions on Probability

Learn and Prepare for any exam you want !

Let $X$ and $Y$ be two random variables such that $X + Y = 100$ . If $X$ follows Binomial distribution with parameters $n = 100$ and $p = \frac{4}{5}$ , what is the variance of $Y$ ?