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Recent questions tagged conditional-probability

2 votes
2 answers
1
A sender $(\textsf{S})$ transmits a signal, which can be one of the two kinds: $H$ and $L$ with probabilities $0.1$ and $0.9$ respectively, to a receiver $(\textsf{R})$. In the graph below, the weight of edge $(u,v)$ is the probability of receiving $v$ ... $0.7$. If the received signal is $H,$ the probability that the transmitted signal was $H$ (rounded to $2$ decimal places) is __________.
asked Feb 18 in Probability Arjun 467 views
0 votes
1 answer
2
In an entrance examination with multiple choice questions, with each question having four options and a single correct answer, suppose that only $20\%$ candidates think they know the answer to one difficult question and only half of them know it correctly and the ... tick the same. If a candidate has correctly answered the question, what is the (conditional) probability that she knew the answer?
asked Jan 29 in Others soujanyareddy13 41 views
1 vote
1 answer
3
You are given two coins $A$ and $B$ that look identical. The probability that coin $A$ turns up heads is $\frac{1}{4}$, while the probability that coin $B$ turns up heads is $\frac{3}{4}.$ You choose one of the coins at random and toss it twice. If both the outcomes are heads, what is the probability that you chose coin $B?$ $\frac{1}{16}$ $\frac{1}{2}$ $\frac{9}{16}$ $\frac{9}{10}$
asked Sep 13, 2019 in Probability gatecse 241 views
3 votes
1 answer
4
Let $C_{n}$ be the number of strings $w$ consisting of $n$ $X's$ and $n$ $Y's$ such that no initial segment of $w$ has more $Y's$ than $X's.$ Now consider the following problem. A person stands on the edge of a swimming pool holding a bag of $n$ red and $n$ blue balls. He draws a ball out ... $\frac{C_{n}}{\binom{2n}{n}}$ $\frac{n\cdot C_{n}}{(2n)!}$ $\frac{n\cdot C_{n}}{\binom{2n}{n}}$
asked Sep 13, 2019 in Probability gatecse 180 views
2 votes
1 answer
5
There are $7$ switches on a switchboard, some of which are on and some of which are off. In one move, you pick any $2$ switches and toggle each of them-if the switch you pick is currently off, you turn it on, if it is on, you turn it off. Your aim is to execute a sequence of moves and ... (off,on,off,on,off,off,on) (off,on,on,on,on,on,off) (on,off,on,on,on,on,on) (off,off,off,off,off,on,off)
asked Sep 13, 2019 in Probability gatecse 325 views
0 votes
1 answer
6
A multiple choice exam has 4 choices for each question. A student has studied enough so that the probability they will know the answer to a question is 0.5, the probability that they will be able to eliminate one choice is 0.25, otherwise all 4 choices seem ... want the test to measure what the student knows. If the student answers a question correctly what's the probability they knew the answer?
asked Feb 18, 2019 in Probability Na462 1.2k views
0 votes
1 answer
7
Oscar has lost his dog in either forest A (with a priori probability 0.4) or in forest B (with a priori probability 0.6). On any given day, if the dog is in A and Oscar spends a day searching for it in A, the conditional probability that he will find the dog that day is 0.25. Similarly, if the ... *0.25+(1/2)*0.15; but the answer given is=(0.5*0.4*0.25)+(0.5*0.6*0.15); what is wrong with my logic?
asked Feb 16, 2019 in Probability DIYA BASU 379 views
1 vote
1 answer
8
Q32 [Mock 4]. Naveen's coin box contains 8 fair standard coins (heads and tails) and 1 coin which has heads on both sides. He selects a coin randomly and flips it 4 times, getting all heads. If he flips this coin again, what is the probability it will be heads? 1/3 2/3 ... )*(1/2)+(1/9)*(1) Probability of choosing fair coin and P(heads)+ P(unfair)*P(heads). Please help me understand this question.
asked Jan 22, 2019 in Probability great_gater 491 views
0 votes
0 answers
9
Probability density function of a random variable X is distributed uniformly between 0 and 10 The probability that X lies between 2.5 to 7.5 and the mean square value of X are respectively. please give step by step answer in a detailed manner.
asked Jan 21, 2019 in Probability learner_geek 202 views
2 votes
3 answers
10
In a lottery, 10 tickets are drawn at random out of 50 tickets numbered from 1 to 50. What is the expected value of the sum of numbers on the drawn tickets?
asked Jan 20, 2019 in Mathematical Logic learner_geek 1.1k views
1 vote
1 answer
11
A player tosses two fair coins. He wins rs 2 if 2 heads occur and rs 1 if 1 head occurs. On the other hand, he loses rs 3 if no heads occur. if the player plays 100 times.then the amount he wins______________(RS).
asked Jan 20, 2019 in Mathematical Logic learner_geek 262 views
0 votes
1 answer
12
Prabha is working in a software company. Her manager is running a dinner for those employees having atleast one son. If Prabha is invited to the dinner and everyone knows she has two children. What is the probability that they are both boys?
asked Jan 19, 2019 in Mathematical Logic ghostman23111 228 views
2 votes
1 answer
13
An urn contains $m$ WHITE and $n$ BLACK balls. A ball is drawn at random and is put back into the urn along with $k$ additional balls of the same color as that of the ball drawn. If now a ball is drawn, the probability that it is WHITE is? $(m+k)/(m+n+k)$ $(n+k)/(m+n+k)$ $m/(m+n+k)$ $m/(m+n)$
asked Dec 27, 2018 in Probability Ruturaj Mohanty 286 views
2 votes
1 answer
14
A full joint distribution for the Toothache, Cavity and Catch is given in the table below : What is the probability of Cavity, given evidence of Toothache ? (a) <0.2, 0.8> (b) <0.6, 0.4> (c) <0.6, 0.8> (d) <0.4, 0.8>
asked Dec 25, 2018 in Probability Sanjay Sharma 724 views
2 votes
0 answers
15
What is the conditional probability that exactly four heads appear when a fair coin is flipped five times, given that the first flip came up heads? shouldn’t the answer be 1/16? my approach probability that we get 4 head after 4 toss=(1/2)^4 probability that outcome of first toss is head=½ P(A/B)=P(A ∩ B)/P(B)=$\frac{(1/2)^4*1/2}{1/2}$ answer is given ¼? where am I going wrong?
asked Dec 1, 2018 in Probability aditi19 201 views
0 votes
0 answers
16
It had been found from past experience that of the articles produced by a factory, 20% comes from Machine 1; 30% comes from Machine 2 and 50% from Machine 3. The percentages of satisfactory articles among those produced are 95 for machine 1, 85 for machine 2 ... the probability that is satisfactory? ii) Assume the article is satisfactory. What is the probability that it was produced by machine 1?
asked Nov 30, 2018 in Probability Tuhin Dutta 183 views
0 votes
1 answer
17
A factory has three machines, M1, M2, and M3, that produce items (say, light bulbs). It is impossible to tell which machine produced a particular item, but some are defective. Here are the known numbers: machine proportion of items made prob. any made item is defective M1 0.2 0. ... M3 0.5 0.003 You pick an item, test it, and find it is defective. What is the probability that it was made by M2?
asked Sep 24, 2018 in Probability Pooja Khatri 198 views
1 vote
1 answer
18
Roll a die, then select at random, without replacement, as many cards from the deck as the number shown on the die. What is the probability that you get at least one Ace?
asked Sep 23, 2018 in Probability Pooja Khatri 135 views
0 votes
1 answer
19
Flip a fair coin. If you toss Heads, roll 1 die. If you toss Tails, roll 2 dice. Compute the probability that you roll exactly one 6.
asked Sep 23, 2018 in Probability Pooja Khatri 122 views
0 votes
1 answer
20
An urn contains 10 black and 10 white balls. Draw 3 b) with replacement . what is probability that all three are white
asked Sep 23, 2018 in Probability Pooja Khatri 115 views
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