Discrete Random Variables and Their Distributions Flashcards

(7 cards)

1
Q

What is a random variable

A
  • A variable whose values are the outcomes of a random process
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2
Q

What is the difference between discrete and continous random variables

A
  • Discrete: Variables can take a finite or countable number of distinct values
  • Continuous: Variables can take any value in an interval
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3
Q

What is a probabilty distribution

A
  • A function that assigns probabilities to each of the possible values of a random variable
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4
Q

What are the two properites of a discrete probability distribution

A
  • 0 <= p(y) <= 1 for all y
  • The sum of p(y) = 1
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5
Q

What is the mean of a discrete random variable called and how is it worked out

A
  • The expected value, E(Y)
  • Sum of y*p(y) from y to a predefined value
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6
Q

How can E(cY) and E(aY+b) be written

A
  • E(cY) = cE(Y)
  • E(aY+b) = aE(Y) + b
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7
Q

How is variance calculated

A
  • V(Y) = E(Y^2) - E(Y)^2
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