# Statistic question

#### isabella

Can anybody tell me what is the relationship between probability and frequency and hence what is the meaning of probabilty frequency.

#### uart

Frequency (or more correctly relative frequency) could be considered an experimental measurement of probability. Over a small number of trials the relative frequence measurments may depart considerably from the theoretical probabilty, but over a large number of trials the relative frequence should tend toward the theoretical probabilty.

For example in a coin tossing experiment the theoretical probabilty of throwing a "head" is 0.5 if the coin is fair. If we throw the coin ten times then on average we'd expect to see heads occur five times, giving a relative frequence for heads equal to 5/10, the same as the theoretical probability.

Of course with only 10 tosses there is also a good chance that we'd see other than 5 heads and the relative frequence differ considerably from the probabilty. But if we tossed the coin say one thousand times then we'd expect the relative frequency to be much closer to the theroetical value.

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#### isabella

So what is the meaning of probabilty frequency?

#### uart

isabella said:
So what is the meaning of probabilty frequency?
I assummed you were talking about "relative frequency" as applied to probability. Do you have a link or reference to somewhere the term "probability frequency" is used or defined?

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#### Maxos

Maybe, you mean "probability density"?

#### isabella

i want to know if there a formula for frequentistic probability

#### Maxos

You should be more precise, the notions you are referring to, are not clear at all, perhaps, if English isn't your mother language then try and post these names in your language.

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