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Prob. of >= 1 successes, exactly k successes in n trails?  TOPIC_SOLVED

Question : An infinite sequence of independent trails is to be performed . Each trail results in a success with the probability p and a failure 1-p . What is the probability that i) at least 1 success occurs in the first n trails ii) exactly k success occur in the first n trails iii) all trails resu...
by zorro
on Sun Jun 20, 2010 10:10 am
 
Forum: Statistics
Topic: Prob. of >= 1 successes, exactly k successes in n trails?
Replies: 2
Views: 2988

find the expected value of g(x)  TOPIC_SOLVED

Problem : If the probability of X is given by f(x) = \begin{cases} x/2, & 0 < x < 1 \\ 1/2, & 1 < x < 2 \\ (3-x)/2, & 2 < x < 3 \\ 0 & elsewhere \end{cases} find the expected value of g(x) = X^2 - 5X + 3 Solution : \int\limits_{0}^{1} . g(x) \frac{x}{2...
by zorro
on Sat Jun 26, 2010 6:21 am
 
Forum: Statistics
Topic: find the expected value of g(x)
Replies: 4
Views: 4991

Re: find the expected value of g(x)  TOPIC_SOLVED

THANKS GUYS FOR ALL UR POST ......I JUST NEEDED TO CHECK IF I WAS DOING IT CORRECTLY OR NO ...... :clap:
by zorro
on Sun Jun 27, 2010 7:23 am
 
Forum: Statistics
Topic: find the expected value of g(x)
Replies: 4
Views: 4991

Need to know which formulae which has been used  TOPIC_SOLVED

Question : The average working-set size X of a program is normally distributed with the unknown mean \mu and a known variance \sigma 2 =81 . The program was executed 36 times and the average working set size for each run recorded. The sample mean was computed to be 100 page frames . Assuming success...
by zorro
on Sun Jun 27, 2010 7:43 am
 
Forum: Statistics
Topic: Need to know which formulae which has been used
Replies: 2
Views: 3439

What is the probability that he really knows the answer

Question: In answering a question on a multiple choice test , an examine either knows the answer or he guesses or he copies. Suppose each question has 4 choices. Let the probability that examine copies the answer is 1/6 and the probability that he guesses is 1/3. The probability that his answer is c...
by zorro
on Sun Jun 27, 2010 9:45 am
 
Forum: Statistics
Topic: What is the probability that he really knows the answer
Replies: 4
Views: 4108

Need to know if my answer are correct or no ?  TOPIC_SOLVED

Question : Suppose A and B are two events with P(A)=0.5 and P(A \cup B)=0.8 i) For what value of P(B) would A and B be mutually exclusive ii) For what value of P(B) would A and B be independent Solution i) if P(A) = 0.5 and P(A \cup B)=0.8 then P(B) = P(A \cup B) - P(A) = 0.8 - 0.5 = 0.3 (Is thi...
by zorro
on Sun Jun 27, 2010 10:50 am
 
Forum: Statistics
Topic: Need to know if my answer are correct or no ?
Replies: 12
Views: 9802

Re: Need to know if my answer are correct or no ?  TOPIC_SOLVED

The rule of independent events ,

But how do i use this as i dont know the value of
by zorro
on Mon Jun 28, 2010 2:01 am
 
Forum: Statistics
Topic: Need to know if my answer are correct or no ?
Replies: 12
Views: 9802

Re: Need to know if my answer are correct or no ?  TOPIC_SOLVED

The rule of independent events P(A \cap B) = P(A) . P(B) , But how do i use this as i dont know the value of P(A \cap B) We also have P(A\cup B)=P(A)+P(B)-P(A\cap B) How should i use this in solving the 2nd question ii) For what value ...
by zorro
on Tue Jun 29, 2010 1:42 am
 
Forum: Statistics
Topic: Need to know if my answer are correct or no ?
Replies: 12
Views: 9802

random var. X is -1, 0, 1 w/ equal probability (check ans)  TOPIC_SOLVED

Question :
X is a random variable which takes 3 values -1,0,1 with equal probability i.e. P(x=-1) = P(X=0) = P(X=1) = 1\3
Find E(X) and Var(X)
Solution :
E(X) = 0 (is this correct?)

var(X) = 0 (is this correct?)
by zorro
on Tue Jun 29, 2010 2:27 am
 
Forum: Statistics
Topic: random var. X is -1, 0, 1 w/ equal probability (check ans)
Replies: 4
Views: 4541

Re: random var. X is -1, 0, 1 w/ equal probability (check an  TOPIC_SOLVED

Please can u tell what is wrong


My work ........
E(X) = 0

1 = 0

2= 2/3

2 = 2/3

var(X) = 2 - 2 = 2/3 - 2/3 = 0
by zorro
on Wed Jun 30, 2010 2:27 am
 
Forum: Statistics
Topic: random var. X is -1, 0, 1 w/ equal probability (check ans)
Replies: 4
Views: 4541
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