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Continuous Random Variable (1). Discrete Random Variables. Probability Mass Function (PMF). Continuous Random Variable. P[X=x]=0. Not possible to define a PMF for a continuous random variable. Discrete Random Variables. Cumulative Distribution Function. PMF to CDF. Comparison .
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Discrete Random Variables • Probability Mass Function (PMF)
Continuous Random Variable P[X=x]=0 Not possible to define a PMF for a continuous random variable
Discrete Random Variables • Cumulative Distribution Function
Comparison Discrete RV: Zero slope Jumps in CDF Continuous RV: A continuous function
Slope of CDF function The slope at any point x indicates the probability that X is near x.
Probability Density Function (PDF) It is not possible to define a PMF function for a continuous variable because P[X=x]=0. We can, however, define a probability density function.
Expected Value Discrete Random Variable
Example Find the expected stoppint point of the pointer
The Expected Value of a function Derived Discrete Random Variable Discrete Example Derived Continuous Random Variable
Key Points • An average is a typical value of a random variable. • The next question: • “What are the chances of observing an event far from the average?” • The variance of a random variable X describes the difference between X and its expected value.