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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
P(A|B)= P(A n B) / P(B)
P(A n B) = probability of both A and B happening
to check for independence you see if P(A|B) = P(B)
What is the chances of Rolling a 3 or 4 from two dice?
Assuming you are rolling a six-sided dice, it is 1/3 for one dice and 2/3 for two dice.
How many outfits can you make with 4 sweaters 6 dress shirts and 3 pairs pants?
There are 30 outfit possibilities. Normally for a problem like this you just have to multiply all the numbers, but the trick to this question is to first add the number of shirts. If you don't, then some of your outfits will be a sweater and dress shirt with no pants, which isn't an outfit. So you have a total of 10 shirts and 3 pairs of pants, and when you multiply them you get a total of 30 outfits.
What is the probability of rolling a 4 or 5 on a six sided cube?
The chance of rolling a certain number on a dice is 1/6, so the chance of rolling a 4 OR 5is 2/6.
But if you have two dice you have the most chance of rolling a seven (6/36 or 1/6)
What is the probability of picking a king from a deck of cards?
4 in 52, or 1 in 13, or about 0.0769.
What is the probability you will be dealt 2 aces from a standard 52-card deck?
The probability is 4/52 for the first ace and 3/51 for the second.
So the probability of 2 aces is 4/52 x 3/51 = 1/221
The probability that a parent carrying a dominant trait will pass that trait on is a 50% chance with each pregnancy
2/12 or 1/6
What is the probability of choosing odd number?
If you chose the number out of an equal numberof odd and even numbers then it would be 50% chance.
Like if you chose an odd number out of the numbers from 1 to 100
What is the probability of getting neither an ace nor a heart?
The probability of not getting on ace is 48 in 52, or 12 in 13, or about 0.9231. The probability of not getting a heart is 39 in 52, or 3 in 4, or 0.75.
These two events, however, are not exclusive, so you can not just multiply them together. You need to look at the big picture. But look at the summary below.
There are 4 aces in the deck, one of which is a heart. There are 13 hearts in the deck, one of which is an ace. The inclusion set is 16 cards that are either an ace or a heart. Flip this over by subtracting from 52 and you get 36 cards that are not an ace nor a heart.
So, the probability of getting neither an ace nor a heart is 36 in 52, or 18 in 26, or 9 in 13, or about 0.6923.
Now, it turns out that you could have just multiplied the probabilities and obtained the same result. This worked because you were looking at inverse probabilities. It would not have worked if the question was to find the probability of getting an ace or a heart.
In summary, I went ahead and showed the thought process involved to illustrate a point - that you need to understand the set of possible outcomes in order to make a correct calculation.
What are the odds of rolling a 7 with two dice?
The odds of rolling a 7 with two dice is 6 in 36, or 1 in 6.
Two six-sided dice will yield 36 different possible combinations in one roll. Note that rolling 1 and 6 is not the same as rolling 6 and 1. Yes, they both equal 7, but for the purposes of determining probability, each throw is unique. There are 6 possible ways to throw a 7, and they are 1-6, 2-5, 3-4, 4-3, 5-2, and 6-1. With 36 different possible outcomes, that means that 6 in 36 of those outcomes results in a 7. The odds of getting a 7 are 6 in 36, or 1 in 6 (reducing the two terms).
We sometimes see the terms "odds" and "probability" interchanged, but it is important to distinguish them mathematically. If you are interested in the probability of rolling a 7 in a single roll of a pair of dice, use the link to the Related question.
What is the probability of scoring 11 when you roll two dice?
Assuming they are fair dice that are numbered 1 to 6, the probability is 2/36 = 1/18
What z score represents the 80th percentile?
To find what z-score represents the 80th percentile, simply solve for 0.8 = F(z), where F(x) is the standard normal cumulative distribution function. Solving gives us:
z = 0.842
How many times would you roll a sum of seven on one number dice?
never.. the highest number on a dice is a 6
Probability of drawing a 10 o r the 6 of diamonds?
Presuming a standard 52 card deck, you have 5 cards in that deck which satisfy your requirement.
Therefore the probability of getting one of those cards is 5/52.
The mean, median, and mode of a normal distribution are equal; in this case, 22. The standard deviation has no bearing on this question.
What is the probability of rolling a prime number on a six sided dice?
The probability is 1 out of two.
The primes you can roll are 2,3, and 5.
What is the mean and standard deviation for the standard normal curve?
Mean = 0
Standard Deviation = 1
What is the probability of throwing one dice twice and getting a 1 both times?
The probability of throwing a dice an getting a 1 is 1/6. The probability of getting
a 1 the second time is 1/6. The probability of both events, getting a 1 the first
time and a 1 the second time is; P(1,1) =
(1/6)∙(1/6) =
1/36 =
0.02777... ~ 2.8%
What is the number that describes the likelihood a certain event will occur?
The probability of that event.
