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USING R: Consider rolling two fair dice, suppose on is red and the other blue. D

ID: 3867732 • Letter: U

Question

USING R:

Consider rolling two fair dice, suppose on is red and the other blue.

D1 = Outcome of the red die

D2 = Outcome of the blue die

Y = D 1 + D2

Use R to build the pmf for D1 as a two-column data.frame, then use this table to compute the mean, the variance, and the standard deviation. Repeat these steps for D2 and Y.

Detailed Instructions:

Build the pmf for D1. It should be a data.frame with two columns, one for possible outcomes (called k) and one for the probability of each outcome (called pk).

Use k and pl to compute mu1=, the mean/expected value of D1. Even better if you can do this using the%*% operator.

Using k, pk and mu=1, compute var1= to find the variance of D1. Then use the variance to compute sd1=the standard deviation.

Repeat steps for D2.

Explanation / Answer

PX(D1) = Z 1 0 2x 9

dx = 1 9 .

PX(D3) = Z 3 2 2x 9

dx = 1 4 9 = 5 9 .

1 PX(D1 D2) = 1 9 + 5 9 = 6 9 .

In the last,

we used that D1 D2 = .