The random variables Y1 and Y2, for −1 ≤ α ≤ 1, have a joint density function given by f(y1, y2) = [1 − α{(1 − 2e−y1)(1 − 2e−y2)}]e−y1 − y2, 0 ≤ y1, 0 ≤ y2, 0, elsewhere, and established that the marginal distributions of Y1 and Y2 are both exponential with mean 1. (a) Find E(Y1) and E(Y2). E(Y1) = E(Y2) = (b) Find V(Y1) and V(Y2). V(Y1) = V(Y2) =

Jordan got 27 out of 90 correct on his test . what fraction of the marks did her get correct

F(x)=5/6x+3 which of the following is true

1. why is a frequency distribution useful? it allows researchers to see the "shape" of the data. it tells researchers how often the mean occurs in a set of data. it can visually identify the mean. it ignores outliers. 2. the is defined by its mean and standard deviation alone. normal distribution frequency distribution median distribution marginal distribution 3. approximately % of the data in a given sample falls within three standard deviations of the mean if it is normally distributed. 95 68 34 99 4. a data set is said to be if the mean of the data is greater than the median of the data. normally distributed frequency distributed right-skewed left-skewed