Probability mass function
Let
be a discrete random variable. The probability mass function
of
is a function
![[eq1]](http://images1.statlect.com/probability_mass_function__3.png)
such
that![[eq2]](http://images2.statlect.com/probability_mass_function__4.png)
In
other words, the probability mass function, when evaluated at the point
,
is equal to the probability that the random variable
takes the value
.
You can find an in-depth discussion of probability mass functions in the lecture entitled Random variables.
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