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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
What is a number 0 to1 that describes how likely an event is to occur?
A number between 0 and 1 represents a decimal probability of how likely an event is to occur. It can be converted into a percentage by multiplying it by 100. For instance 0.5x100 = 50% so 0.5 means that something has a 50% chance of occurring. 0 means that the event definitely won't occur, and 1 means that it definitely will.
What is it called when you pick an object and do not return it in probability?
When you pick an object and do not return it, in probability it is termed "without replacement".
What is the probability of selecting a queen from a deck of cards?
un likely
im 9 and i could work this out
What is the probability of having 3 male offspring in a row?
There are factors such as genetic tendencies, age etc which favour male or female offspring so that the probability of a male offspring is not uniformally 1/2.
Next, the question does not specify how many offspring in all, so the possible sequences could be
[any sequence whether or not containing MMM] followed by [MMM] followed by [any sequence whether or not containing MMM].
As the sequence grows longer, the probability that somewhere in the sequence there are 3 male offspring in a row increases.
For 3 offspring, the probability is 1/8 = 0.125
for 8 offspring, the probability is 107/256 = 0.418
The probabilities would need to be weighted together using the proportion of families that have 3 children, 4 children, and so on.
A fair die is a die where the probability of throwing each of the faces is equal. Dice is two or more die's.
What can be used to make predictions?
A educated guess or hypothesis depending on what it is like something simple (predicting a math or science question).
How do you write 1234 in expand form?
Expanded Notation of 1,234 = (1 x 103) + (2 x 102) + (3 x 101) + (4 x 100)
What are the odds in favor of getting 2 heads when a coin is tossed twice?
One in four. 1:4.
The probability of getting heads when a fair coin is tossed is: P(H) = 1/2.
The probability of getting heads on a second toss is: P(H) = 1/2, this result is
independent of the result of the first toss.
The probability of having both events happen (heads on the first and heads on the
second toss) is: P(H1UH2) = (1/2)∙(1/2) = 1/4 = 0.25 = 0.25%
Rolling an odd number or a 6 on a number cube?
There are 6 numbers total; odd numbers are 1, 3, 5; then a 6 is added so the probability of rolling an odd number or a 6 on a number cube is 4/6 or 2/3 or 66.67%.
What is the probabilty of drawing a 3 from a deck of 52 cards?
There is a 4 in 52 probability (reduce to 1 in 13) of drawing a '3' from a 52-card deck.
Two balls are certainly white. So the remaining balls may be one of the following
{WW, WN, NW, NN}
where W means a white ball and N means non-white
ball
Let the events be:
E- all four balls are white(WW)
F- 3 balls are white(WN,
NW)
G- only two balls are white(NN)
Now, P(E) =
P(G) =
1/4, and P(F) =
1/2
Let A be the event that the two balls drawn are white
P(A|E)
=
4C2/4C2 =
1
P(A|F)
=
3C2/4C2 =
1/2
P(A|G)
=
2C2/4C2 =
1/6
Now By Bayes' Theorem,
required probability =
P(E|A)
=
(1*1/4) / ( 1*1/4 + 1/2*1/2 + 1/6*1/4 )
=
(1/4) / ( 13/24 )
=
6/13
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2nd opinion
Let's say we have 3 boxes with 4 balls each.
Box A has 4 white balls.
Box B has 3 white balls.
Box C has 2 white balls.
The probability of drawing 2 W balls from;
Box A, P(2W│A) =
(4/4)∙(3/3) =
1
Box B, P(2W│B) =
(3/4)∙(2/3) =
1/2
Box C, P(2W│C) =
(2/4)∙(1/3) =
1/6
Say the probability of picking any of the 3 boxes is the same, we have;
P(A) =
1/3
P(B) =
1/3
P(C) =
1/3
Question is, given the event of drawing 2 W balls from a box taken blindly
from the 3 choices, what is the probability that the balls came from box A,
P(A│2W).
Recurring to Bayes Theorem:
P(A│2W) =
[P(A)P(2W│A)]/[P(A)P(2W│A)+P(B)P(2W│B)+P(C)P(2W│C)] =
[(1/3)(1)]/[(1/3)(1)+(1/3)(1/2)+(1/3)(1/6)] =
6/10 =
0.60 =
60%
P(A│2W) =
0.60 =
60%
Two dice tossed Probability sum is 6?
Well both dice have 6 sides for 6 + 6 = 12 and that shall be your denomenator.
The probability that both sides will equal 6 could be..
1,5
2,4
3,3
4,2
5,1
so the answer would be 5/12
* * * * *
Absolute rubbish.
The denominator (not denomenator!) is 6 * 6 = 36 not 12.
So the answer is 5/36.
How is probability usually written?
P(s) = s/t where success = s and total outcomes = t
instead of a fraction it can be written as a decimal.
How many ways can 5 CDs be selected from a stack of 12 different CDs?
The answer is 12C5 = 12*11*10*9*8/(5*4*3*2*1) = 792
Is a binomial distribution symmetric?
No, in general is not. It is only symmetric if the probability of success in each trial is 0.5
What is the event if the probability will equal 1?
It is the probability of an event that will definitely happen.
30%
Chance of boy or girl by paternal parentage?
Comprehensive information is not available. The father's parentage is not recorded for all births - there are enough missing values to cast doubt on the accuracy of the results.
1. In a random sample of 200 persons of a town, 120 are found to be tea drinkers. In a random sample of 500 persons of another town, 240 are found to be tea drinkers. Is the proportion of tea drinkers in the two towns equal? Use 0.01 level of significance.
Why is a z-score range -3 to plus 3?
Strictly speaking, it is not, but the range -3 to +3 accounts for 99.73% of the total probability.
