Probability Distributions

Probability Distributions

1. Discrete probability Distribution

   • Definition: The outcome is finite or all known.
   • Table or formula that lists the probabilities for each outcome of the random variable
     • • P(X=x): P= probability . X= The random variable (head)
       • • The probability of getting three head is 1/8. the probability of getting zero heads, In this case, is also 1/8. as we only get zero once. The probability of getting one head is 3/8 as it appears three times in the experiment

2. continues probability distribution graph is used for normal distribuion

   • the outcome can be infinite. For the probability of people being 6ft tall is continues as people can be 6.01, 6.001 ft, etc.

3. Random Variable (X)

   • Random Variable- A variable whos value is determined by a random experiment
     • Experiment: what is the probability of getting three head (head is X) when flipping three coin

4. Normal Probability distribution

   • The normal distribution is completely defined by the mean (u) and the standard deviation (a).
     • Mean is the average which is the line in the middle. Standard deviation is the width of the curve.
     • 20=the mean
       • standard deviation= 15. since 20-15= 5
         • The shaded area defines the probability P
   • the line represents the probability, when it's high the probability is high when low it's low.
   • Standard normal distribution

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