9 Flashcards
(10 cards)
Mean (mu) of a random variable X?
Expected value (E(X)) and its the average of X.
The mean of a random variable is the?
Center of gravity or bouncing point for a random variable’s distribution.
Quantile?
The numbers are going to be a value between 0 and 1, whole ignoring most P(X <= Q_p)
Median of a distribution?
Median puts half of area on left and other half on right.
!!!With a discrete variable, is it possible for more than one satisfy these conditions?
In terms of proportions, which are the benefits of a median?
50% in one side and 50% in the other side.
A variance is a random variable X in which?
It measures the average squared distance between the mean and the random variable
Can variance be negative?
No, they are always positive.
If variance of a random variable will only be equal to zero if the random variable can only has how many values in its sample space with a positive probability?
One
Units of a variance will be the original units of measured squared.
X = inches, sigma_s^2 = inch^2