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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
relative frequency method
How do you subtract standard deviations?
Square the standard deviations, subtract/add them and calculate the square root of the subtraction/sum.
StDV=sqrt (StDvA^2+StDvB^2)
Does standard deviation have to be between 0 and 1?
Standard deviation doesn't have to be between 0 and 1.
What does the expected value of a binomial distribution with n trials tell you?
average number of successes
99.7% of scores fall within -3 and plus 3 standard deviations around the mean in a normal distribution.
When may the sampling distribution of x̅ be considered to be approximately normal?
the standard deviation of the population(sigma)/square root of sampling mean(n)
If you throw a coin 6 times how many possible outcomes are there?
Whenever you are trying to figure out the answer to an outcome problem, you just multiply how many sides it has by how many times you are tossing the coin.... 2 x 6 = 12 times.
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Very reasonable. Warm, fuzzy, and intuitively satisfying. But, sadly, wrong.
Every toss of a coin has 2 possible outcomes.
If you write down the results of 6 tosses like: H T T H T H with an 'H' for each heads
and a 'T' for each tails, the number of different patterns you could write down for
six tosses is
2 x 2 x 2 x 2 x 2 x 2 = 64 .
If you don't care about the sequence, and you just want to know how many
different splits of 'heads' vs 'tails' you could get in 6 tosses, then there are seven
different possible outcomes:
-- no heads, 6 tails
-- 1 heads, 5 tails
-- 2 heads, 4 tails
-- 3 heads, 3 tails
-- 4 heads, 2 tails
-- 5 heads, 1 tails
-- 6 heads, no tails
Zero
What is the probability of rolling a sum of 10 when you roll two dice?
Each cube can land in 6 different ways.
Two cubes can land in (6 x 6) = 36 different ways.
There are 3 different ways of rolling a ten:
4 - 6
5 - 5
6 - 4
The probability of rolling a ten is (3 / 36) = 1/12 = 8 and 1/3 percent
What does probability have to do with heredity?
There is a chance of what u will recieve from ur parents genes.
Mean and standard deviation of probability density function?
Suppose the probability density function is f(x), defined over a domain D
Then the mean is E(X) = x*f(x) integrated with respect to x over D.
Calculate E(X2) = x2*f(x) integrated with respect to x over D.
Then Variance(X) = E(X2) - [E(X)]2
and Standard Deviation = sqrt(Variance).
9 In how many different ways can you arrange 7 books on a shelf?
Consider one placement at a time. The first book on the shelf could be any of seven. The second could be any of the remaining six. This continues with the rest. The total combinations are:
7! = 7*6*5*4*3*2*1 = 5040
This is the same as 1 minus the probability that neither of them are greater than three. This is 1, minus the probability of getting greater than three, squared. Rolling higher than three has a 1/2 probability, so:
P(at least one greater than 3) = 1 - (1/2)2 = 1 - 1/4 = 3/4
Coin tosses are independent events. The probability of a head remains 1/2
Average number of arriving customers in 4 minute interval is 2.8 and poison distributed what is the probability that exactly six customer will arrive in a 4 minute interval?
What is the sample size for a population of 60010?
well a sample size can be any size depending on the requirements. A sample size could be 10 people of that entire population or it could be 1000 people.
Is convenience sampling method not a random sampling?
You are correct; convenience sampling is not random sampling.
