Answer:
{(2,0),(-5,1),(7,8),(6,0),(-7,1)
Y varies directly with x" means y = constant * x or y = kx ----- (1)1. when x = -1/2, y = 2Put it in (1):2 = k * (-1/2)multiply by 2:4 = k * (-1)4 = -kk = -4y = -4x
"find the value of y when x= -0.3"y = -4x = (-4) * (-0.3) = 1.2
So for each problem, start with y = kxThey give you one x and one y value.Put it in y = kx and find k.Then put x = -0.3 and find y.
Given:
μ = 200 lb, the mean
σ = 25, the standard deviation
For the random variable x = 250 lb, the z-score is
z = (x-μ)/σ =(250 - 200)/25 = 2
From standard tables for the normal distribution, obtain
P(x < 250) = 0.977
Answer: 0.977
In a hand of 5 cards, you want 4 of them to be of the same rank, and the fifth can be any of the remaining 48 cards. So if the rank of the 4-of-a-kind is fixed, there are
possible hands. To account for any choice of rank, we choose 1 of the 13 possible ranks and multiply this count by
. So there are 624 possible hands containing a 4-of-a-kind. Hence A occurs with probability

There are 4 aces in the deck. If exactly 1 occurs in the hand, the remaining 4 cards can be any of the remaining 48 non-ace cards, contributing
possible hands. Exactly 2 aces are drawn in
hands. And so on. This gives a total of

possible hands containing at least 1 ace, and hence B occurs with probability

The product of these probability is approximately 0.000082.
A and B are independent if the probability of both events occurring simultaneously is the same as the above probability, i.e.
. This happens if
- the hand has 4 aces and 1 non-ace, or
- the hand has a non-ace 4-of-a-kind and 1 ace
The above "sub-events" are mutually exclusive and share no overlap. There are 48 possible non-aces to choose from, so the first sub-event consists of 48 possible hands. There are 12 non-ace 4-of-a-kinds and 4 choices of ace for the fifth card, so the second sub-event has a total of 12*4 = 48 possible hands. So
consists of 96 possible hands, which occurs with probability

and so the events A and B are NOT independent.