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Probability
The probability of a certain event is a number expressing the likelihood that a specific event will occur, expressed as the ratio of the number of actual occurrences to the number of possible occurrences. In mathematics, it is a measure of how often an event will happen and is the basis of statistics.
14,643 Questions
How many different ways are there to arrange the letters D D and A?
There are 3 factorial ways to arrange the letters DDA, where factorial (denoted as 3!) is the product of all positive integers up to 3 (3 x 2 x 1). So, there are 6 different ways to arrange the letters DDA: DDA, DAD, ADD, DDA, DAD, ADD.
What is the probability of spinner landing on pink?
It depends on how many colors there are on the spinner you are using
What is the probability of getting one-eye jack?
There are two one-eye jacks in a standard deck of 52 cards. So the probability of getting one is 2/52 = 1/26
The probability of rolling a sum of 8 on one roll of a pair of dice is 5/36.
The probability of not rolling a sum of 8 on one roll of a pair of dice is 31/36.
The probability of rolling a sum of 8 twice on two rolls of a pair of dice is
(5/36)(5/36) = (5/36)2 .
The probability of rolling first a sum of 8 and then rolling a sum that is not 8 on the
second roll is (5/36)(31/36).
The probability of rolling a sum that is not 8 on the first roll and rolling a sum of 8
in the second roll is (31/36)(5/36).
So The probability of rolling a sum of 8 at least one of two rolls of a pair of dice is
(5/36)2 + (5/36)(31/38) + (31/36)(5/36) = 0.258487654... ≈ 25.8%.
What is the difference between stratified and random sampling?
In a stratified sample, the sampling proportion is the same for each stratum. In a random sample it should be but, due to randomness, need not be.
What is the probability that a family of 2 children has no boys?
There is a One in two chance that the first child is a girl (not a boy), then there is the same chance (1/2) that the second child is not a boy. The chance that neither is a boy is (1/2) * (1/2) = 1/4.
Another way to look at it is like a table or grid. There are four possibilities, represented by the grid. The rows represent the sex of the first child, and the columns the second child. Where they intersect is the combination of the two. So you want any square where there are no boys (both girls). So there is only 1 square out of the 4 where this is true (denoted by a Y for Yes, the others denoted by n for no):
* | B | G |
B | n | n |
G | n | Y |
Stratified
How many outcomes are in the sample space for tossing two coins?
The sample space consists of the following four outcomes: TT, TH, HT, HH
What is the probability of 2 coins landing on heads?
well since the coins have two sides,there is a 50% chance of it landing on heads
What is the probability that a male offspring will have hemophilia?
Without any further information, the probability is between 0.0001 and 0.0002
What are the chances of picking a king and a diamond from a deck of cards?
the probability of picking a king from a deck of cards is 4/52,which is 1/13 because there are 4 kings. Which are king of heart, king of diamond,king of club and king of spade. And the probability of picking a diamond is 13/52,which is 1/4.
How do you find the probability of a spinner?
You find out how many choices there are in a spinner and then you take what it wants you to find the probability of and tur it into a fraction
For example:
You have a spinner with 4 triangles in it....2 are red and 2 are green,What is the probability of landing on a green triangle
2 out of 4
What are the odds against rolling a 4 in a fair die?
Well I'm supposing it's a 6 sided dye. Since there are 6 sides it's a 1 out of 6 chance or 16% chance that you would roll a 4.
The odds against rolling a 4, the complementary event, are 5 out of 6, a chance
of: 1 - 0.1666.. = 0.8333... ≈ 83.3%.
What is the probability of having exactly 2 boys out of 6 children?
The answer depends on whether the children are picked at random. If they were selected from inside a girls' school the probability should be quite close to 0. Likewise, if the children were picked inside a boys' school.
If six children are picked at random from a large group of children with an equal number of boys and girls, then the answer is
6C2*(1/2)6 = 15/32 = 0.47, approx.
How do you solve for probabilities in binomial distributions?
Suppose you have n trials of an experiment in which the probability of "success" in each trial is p. Then the probability of r successes is:
nCr*pr*(1-p)n-r for r = 0, 1, ... n.
nCr = n!/[r!*(n-r)!]
What is marginal probability function?
If f(x, y) is the joint probability distribution function of two random variables, X and Y, then the sum (or integral) of f(x, y) over all possible values of y is the marginal probability function of x.
The definition can be extended analogously to joint and marginal distribution functions of more than 2 variables.
5 marbles. 3 red marbles, 2 white marbles.
The probability of drawing a white marble is P(W) = 2/5 = 0.40
If the white marble is not returned to the rest of the marbles (no substitution), the
probability that the second marble drawn is a red one is P(R) = 3/4 = 0.75.
The probability that the event of drawing first a white marble and without substitution
the second draw turns a red marble is P(1stW,2ndR) = (2/5)∙(3/4) = 6/20 = 3/10 = 0.30 = 30.0%.
If the process of drawing the marbles is with substitution, the probability of the
second draw turning a red marble is P(R) = 3/5 = 0.60 = 60.0%
The probability that the event of first drawing a white marble and after returning the
marble back to the original group of marbles (with substitution) the second draw turns a red marble is P(1stW,2ndR) = (2/5)∙(3/5) = 6/25 = 0.24 = 24.0%.
If there are 48 tacks, (15+5+20+8), you want to divide the number of one color over the total to find the percentage of that color out of the whole.
If there are 8 silver tacks, take 8 over 48, which equals .167.If there are 20 white tacks, take 20 over 48, which equals .4167
Now you know the percentage of silver out of the whole, and the percentage of white out of the whole.
To figure out the white and silver together, add them together!
White and Silver tacks make up about .583, or 58.3%
And that's your answer. You have a 58% chance of picking a white or silver tack from the box when picked at random.
If events A and B are statistically indepnedent, then the conditional probability of A, given that B has occurred is the same as the unconditional probability of A. In symbolic terms,
Prob(A|B) = Prob(A).
How many permutations are in the word geometry?
geometry has 8 letters, 2 of which are the same (e)
So, the answer is 8!/2! = 20,160
