Jane chooses a number X at random from the set of numbers
{1, 2, 3, 4}, so that
P(X = k) =
1
4
for k = 1, 2, 3, 4.
She then chooses a number Y at random from the subset of
numbers {X, ...,
4
}; for example, if
X = 3, then Y is chosen at
random from {
3,
4}
.
(i) Find the joint probability distribution of X and Y and display
it in the form of a two-way table.
[5 marks]
(ii) Find the marginal probability distribution of Y , and hence
find E(Y ) and V ar(Y ).
[4 marks]
(iii) Show that Cov(X, Y ) = 5/8.
[4 marks]
(iv) Find the probability distribution of U = X + Y . [7
The US government is interested in understanding what predicts death rates. They have a set of data that includes the number of deaths in each state, the number of deaths resulting from vehicle accidents (VEHICLE), the number of people dying from diabetes (DIABETES), the number of deaths related to the flu (FLU) and the number of homicide deaths (HOMICIDE).
Your run a regression to predict deaths and get the following output:
At alpha=0.05, what is indicated by the significance F in this problem?
A. The regression model does not significantly predict deaths.
B. The regression model significantly predicts deaths.
C. Two of the four independent variables significantly predict deaths.
D. Three of the four independent variables significantly predict deaths.