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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
Let X = the number of green marbles.
X+3 = the number of blue marbles.
X + (X+3) = 23
2X + 3 = 23
2X = 20
X = 10 or the number of green marbles.
What is the probability of rolling a 3 and then 1 of six side dice?
The probability of rolling the 3 is (1/6).
The probability of rolling the 1 is (1/6).
The probability of rolling the 3 and then the 1 is (1/6) x (1/6) = (1/36) = about 2.78% (rounded)
If you toss a coin 50 times what will it land on?
Probably on the floor at least once.
It's possible for the results to be anything between 50 heads and 50 tails.
The most probable result ... if the coin is honest, fair, and balanced, like Fox News #@%$&#*&@ ...
is 25 heads and 25 tails.
There is no way to predict exactly what the result will be. If it were possible to know in advance,
then coin-tosses could not be used to gamble or to decide the answer to a question.
Probability of having a boy or a girl?
The probability of having a boy or a girl is always 50/50 because the female has to X sex chromosomes and the male has one X and one Y sex chromosome. If you do a Punnet Square, there will be two squares with XY and two squares with XX. With four squares in all that makes a 50/50 chance.
In a standard normal distribution what is the value of the mean and standard deviation?
idk about normal distribution but for
Mean "M" = (overall sum of "x") / "n"
frequency distribution: 'M' = Overall sum of (' x ' * ' f ') / overall sum of ( ' f ' )
M = Mean
x = Mid Point
f = frequiency
n = number of variables
ALL FOR STANDARD DEVIATION
* * * * *
A general Normal distribution is usually described in terms of its parameters, and given as N(mu, sigma2) where mu is the mean and sigma is the standard deviation.
The STANDARD Normal distribution is the N(0, 1) distribution, that is, it has mean = 0 and variance (or standard deviation) = 1.
Give three properties of a normal distribution function?
1.it is bell shaped.2.m.d=0.7979 of s.d
3.total area under the normal curve is equal to 1.
There is a 1/16 probability that 5 tosses end with the same result - 1/32 that they are all tails. In this kind of example, most statisticians would not reject the hypothesis of a fair coin unless the probability was less than 5% or 1/20.
The null hypothesis is that the coin is a fair coin. If the alternative hypothesis is that something is wrong with the coin, the probability of a result such as the one observed (and its mirror image) is 6.25%. So you would not reject the null hypothesis at the 5% level.
However, if your alternative is that the coin favours tails, the probability of as extreme an outcome is 0.03125 or 3.125% and you would reject the null hypothesis.
This is a marginal case at the 5% level and you may wish to toss the coin a few more times to reduce the probability of the outcome occurring purely by chance.
What is standard deviation of the mean?
If repeated samples are taken from a population, then they will not have the same mean each time. The mean itself will have some distribution. This will have the same mean as the population mean and the standard deviation of this statistic is the standard deviation of the mean.
Two coins are tossed what is the probability of getting a head?
is it 50% or 100%
dang, i just confused myself.
what if you toss 3 coins all at the same time... what's the probability of getting a head then, is it > 100% ? Doh!
3/10 or 0.3 is the probability of picking a purple marble.
What is the distribution of sample means constructed by sampling 5 items from a population of 15?
the standard error will be 1
The first 10 positive whole numbers are: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
The even numbers among those are 2, 4, 6, 8, 10.
So there are 5 ways of choosing an even number from among the first 10 positive whole numbers.
What is the z score representing the 10th percentile of the standard normal distribution?
Right around -1.28
What is probability of tossing 10 more tails in a row?
With an honest coin, the probability of tossing 10 consecutive tails is
(1/2)10 = (1/1024) = 0.0009766 = 0.09766 percent(rounded)
regardless of what may have happened before.
When is it appropriate to use stratified random sampling?
it can be used when members of the population are heterogenous
If you flip a a coin 20 times what is the probability that the coin will land on heads?
There is a fifty percent chance of the coin landing on "heads" each time it is flipped.
However, flipping a coin 20 times virtually guarantees that it will land on "heads" at least once in that twenty times. (99.9999046325684 percent chance)
You can see this by considering two coin flips. Here are the possibilities:
Heads, heads.
Heads, tails.
Tails, tails.
Tails, heads.
You will note in the tossing of the coin twice that while each flip is fifty/fifty, that for the two flip series, there are three ways that it has heads come up at least once, and only one way in which heads does not come up.
In other words, while it is a fifty percent chance for heads each time, it is a seventy five percent chance of seeing it be heads once if you are flipping twice.
If you wish to know the odds of it not being heads in a twenty time flip, you would multiply .5 times .5 times .5...twenty times total. Or .5 to the twentieth power.
That works out to a 99.9999046325684 percent chance of it coming up heads at least once in the twenty times of it being flipped.
What is the probability of rolling two dice and the sum is greater than 8?
The probability of rolling a number greater than 8 on one roll of a pair of dice is 0.277777.... Let's see how we get that probability, and, though it may be a little long winded, it's important to understand what's going on.
With one roll of a pair of dice, we have 36 possible outcomes. They are 1-1, 1-2, 1-3,..., 6-4, 6-5, 6-6. To roll a number greater than 8, we have to roll a 9, 10, 11, or 12. There are 10 ways to roll one of those numbers. We could see 3-6, 4-5, 5-4, or 6-3 (to make 9), or 4-6, 5-5, or 6-4 (to make 10), or 5-6 or 6-5 (to make 11), or 6-6 to make 12. That's a total of 10 probable outcomes yielding a number greater than 8. As there are 36 possible outcomes, and 10 yield our required number, the odds of rolling a number greater than 8 are 10 in 36, or 5 in 18 (which is 10 divided by 36 reduced). To discover the probability of a number greater than 8, we need to divide the 10 by 36, and this gives us 0.277777.... as that probability.
Note that the question asked for the probability of the given event, and not the odds. Probability is different from "the odds" of something happening when we consider the mathematics, and the two must be distunguished. We note that the odds "appear" when we calculte probability, but the two are different. There is one more idea.
The probability of something happening is a number that is the ratio of the number of times that a given outcome will appear divided by the number of all possible outcomes. With dice, the number of all the combinations that can come up is 36. That means the probability of rolling any number is the number of times that the number can come up divided by all the possble combinations, or that 36.
All probabilities range between zero (0) and one (1), inclusive. If something cannot happen, the probability of it happening is zero. Like rolling a 13 with one roll of the dice. If the probability of something happening, it will happen. Like rolling an odd or an even number with one roll of the dice. All the possible combinations are odd or even, so the probability of rolling an odd or an even number is one. You will get one or the other.
If it is a fair coin, the probability is exactly 50%. The coin has no memory of what it did in the last flip. ■
Ace combat 4 how do you eject?
To eject just press L1 R1 L2 and R2 all at the same time. Hope this helps.
