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Suppose a random variable Z takes on the values 1 2 3 4 and 5 what is the expected value of Z defined as?
Wiki User
∙ 13y ago
The expected value depends on the probability mass function of Z. It is the average of the possible outcomes weighted by their probabilities.
In other words if you denote the probability mass function as p(z) then:
E[Z] = p(1)*1 + p(2) * 2 + p(3) * 3 + p(4) * 4 + p(5)*5
Where E[] denoted the expected value function. Note the sum is over all possible events (Z = 1 through 5).
Note also that for p(z) to be a proper probability mass function (PMF) it must not take on negative values and the sum over its domain must be equal to 1.
Wiki User
∙ 13y ago
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Is the expected value of a discrete random variable equal to the mean of the random variable?
yes?
Limitation of expected value in decision making?
Expected value of a random variable requires that the random variable can be repeated in experiment indefinitely. If the random variable can only be repeated finite times, e.g. once, there is an inadequacy of the expected value principle for a decision maker.
What is a random variable?
A random variable is a function that assigns unique numerical values to all possible outcomes of a random experiment. A real valued function defined on a sample space of an experiment is also called random variable.
Suppose a normal random variable has a mean of 72 inches and a standard deviation of 2 inches Suppose the random variable X measures the height of adult males in a certain city One may therefore con?
Suppose a normal random variable has a mean of 72 inches and a standard deviation of 2 inches. Suppose the random variable X measures the height of adult males in a certain city. One may therefore conclude that approximately 84% of the men in this population are shorter than?
What is a random variable in probability theory?
Random Variable in probability theory is defined as follows: Assuming you have variables Xi where i is an integer ie: i=1,2,3.......n a variable Xi is called a random variable iff(if and only iff) and random selection yields a variable Xi for i=1,2.........,n with the same likelihood of appearance. i.e prob(X=Xi)=1/n
Is the expected value of a discrete random variable equal to the mean of the random variable?
yes?
Limitation of expected value in decision making?
Expected value of a random variable requires that the random variable can be repeated in experiment indefinitely. If the random variable can only be repeated finite times, e.g. once, there is an inadequacy of the expected value principle for a decision maker.
What is a random variable?
A random variable is a function that assigns unique numerical values to all possible outcomes of a random experiment. A real valued function defined on a sample space of an experiment is also called random variable.
The mean or expected value of the distribution of a discrete random variable is?
30.47
What is the difference between a random variable and random process?
A random process is a sequence of random variables defined over a period of time.
Suppose a normal random variable has a mean of 72 inches and a standard deviation of 2 inches Suppose the random variable X measures the height of adult males in a certain city One may therefore con?
Suppose a normal random variable has a mean of 72 inches and a standard deviation of 2 inches. Suppose the random variable X measures the height of adult males in a certain city. One may therefore conclude that approximately 84% of the men in this population are shorter than?
Is the mean of probability distribution is called its expected value?
No. The mean is the expected value of the random variable but you can also have expected values of functions of the random variable. If you define X as the random variable representing the result of a single throw of a fair die, the expected value of X is 3.5, the mean of the probability distribution of X. However, you play a game where you pay someone a certain amount of money for each throw of the die and the other person pays you your "winnings" which depend on the outcome of the throw. The variable, "your winnings", will also have an expected value. As will your opponent's winnings.
What is a random variable in probability theory?
Random Variable in probability theory is defined as follows: Assuming you have variables Xi where i is an integer ie: i=1,2,3.......n a variable Xi is called a random variable iff(if and only iff) and random selection yields a variable Xi for i=1,2.........,n with the same likelihood of appearance. i.e prob(X=Xi)=1/n
Is the gender of college students a discrete random variable a continuous random variable or not a random variable?
It is a discrete random variable.
When random variable is variable?
When it is random it is variable.
How often the value of a random variable is at or below a certain value.?
The probability of a random variable being at or below a certain value is defined as the cumulative distribution function (CDF) of the variable. The CDF gives the probability that the variable takes on a value less than or equal to a given value.
Can a discrete variable be a negative number?
Yes. For example, consider rolling a die twice, with the random variable defined as the first outcome minus the second.
