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- •Indicate the formula of computing variance of a random variable X with expectation µ.
- •Indicate the expectation of a Poisson random variable X with parameter .
- •Indicate the variance of a Poisson random variable X with parameter .
- •Indicate the formula for conditional expectation.
- •If a fair die is tossed twice, the probability that the first toss will be a number less than 4 and the second toss will be greater than 4 is
- •If one person is selected randomly, the probability that it did not pass given that it is female is:
- •If X and y are independent random variables with ,,and,,,. Thenis
- •If p(e) is the probability that an event will occur, which of the followings must be false?
- •If one person is selected randomly, what is the probability that it did not pass given that it is male.
- •In the first step, Joe draws a hand of 5 cards from a deck of 52 cards. What is the probability that Joe has exactly one ace?
- •If the variance of a random variable X is equal to 3, then Var(3x) is :
- •Indicate the correct statement related to Poisson random variable .
- •In each of the 20 independent trials the probability of success is 0.2. Find the variance of the number of successes in these trials.
- •Indicate the pdf for standard normal random variable.
- •Indicate the function that can be cdf of some random variable.
- •Indicate the function that can be pdf of some random variable.
- •If two random variables X and y have the joint density function, , find the conditional pdf.
- •If two random variables X and y have the joint density function, , find the conditional pdf.
In the first step, Joe draws a hand of 5 cards from a deck of 52 cards. What is the probability that Joe has exactly one ace?
0.2995
0.699
0.23336
1/4
0.4999
The number of clients arriving each hour at a given branch of a bank asking for a given service follows a Poisson distribution with parameter λ=3. It is assumed that arrivals at different hours are independent from each other. The probability that in a given hour at most 2 clients arrive at this specific branch of the bank is:
0.64726
0.81521
0.42319
0.18478
0.08391
Table shows the cumulative distribution function of a random variable X. Determine
.
X |
1 |
2 |
3 |
4 |
F(X) |
1/8 |
3/8 |
3/4 |
1 |
1/8
7/8
1/2
3/4
1/3
Table shows the cumulative distribution function of a random variable X. Determine
.
X |
1 |
2 |
3 |
4 |
F(X) |
1/8 |
3/8 |
3/4 |
1 |
1/8
1
1/2
3/4
0
Which of the following statements is always true for A and
?
P(AAc)=1
P(Ac)=P(A)
P(A+Ac)=0
P(AAc)=0
None of the given statements is true
Consider the universal set U and two events A and B such that
and
. We know that P(A)=1/3. Find P(B).
2/3
1/3
4/9
Cannot be determined
1
A box contains 5 red and 4 white marbles. Two marbles are drawn successively from the box without replacement and it is noted that the second one is white. What is the probability that the first is also white?
1/3
3/8
5/8
1/8
1
If P(A)=1/2 and P(B)=1/2 then
1/4, always
1/4, if A and B are independent
1/2, always
1/2, if A and B are independent
None of the given answers
Suppose that P(A|B)=3/5, P(B)=2/7, and P(A)=1/4. Determine P(B|A).
24/75
24/35
6/35
12/75
None of the given answers
A class contains 8 boys and 7 girls. The teacher selects 3 of the children at random and without replacement. Calculate the probability that the number of boys selected exceeds the number of girls selected.
512/3375
28/65
8/15
1856/3375
36/65
If the variance of a random variable X is equal to 3, then Var(3x) is :
12
6
3
27
9
Let X and Y be continuous random variables with joint cumulative distribution function
for
and
. Find P(X>2).
3/125
11/50
12/25
Indicate the correct statement related to Poisson random variable .
,
,
,
,
is const
None of the given answers is correct
Let X be a continuous random variable with PDF f(x) = cx (0 ≤ x ≤ 1), where c is a constant. Find the value of constant c.
1
2
1/2
3/2
4
We are given the pmf of two random variables X and Y shown in the tables below.
Х |
1 |
3 |
|
|
У |
2 |
4 |
px |
0,4 |
0,6 |
|
|
py |
0,2 |
0,8 |
Find E[X+Y].
5,8
2,2
2
8,8
10
The pdf of a random variable X is given by
. Calculate the parameter
.
0
4
1,5
2
3,5
Four persons are to be selected from a group of 12 people, 7 of whom are women. What is the probability that three of those selected are women?
0.35
0.65
0.45
0.25
0.1211
Suppose that the random variable T has the following probability distribution:
t
| 0 1 2
--------------------------- P(T = t) | .5 .3
.2 Find
.
0.8
0.5
0.3
0.2
0.1
Suppose that the random variable T has the following probability distribution:
t | 0 1 2 --------------------------- P(T = t) | .5 .3 .2 Compute the mean of the random variable T.
0.8
0.5
0.7
0.1
1
Three dice are rolled. What is the probability that the points appeared are distinct.
1
5/9
2
1/3
1/2
Probability density function of the normal random variable X is given by
. What is the standard deviation?
5
3
25
50
9
The event A occurs in each of the independent trials with probability p. Find probability that event A occurs at least once in the 5 trials.
None of the given answers is correct
The cdf of a random variable X is given by
Find the probability P(1.7<X<1.9).
0,16
0,8
1
0,4
0.6