Statistics Exam 2

Statistics Exam 2

1. Standard Deviation (s)

2. Empirical Rule - If a data set is normally distributed then...

   • 1) Approx. 68% of the data will fall within one standard deviation of the mean
   • 2) Approx. 95% of the data will fall within two standard deviations of the mean
   • 3) Approx. 99% of the data will fall within three standard deviations of the mean
   • ! Only wonks if graph is bell shaped!

3. Probability (P)- The proportion of times an event occurs of an experiment is repeated a "large" number of times

   • Two rules of Probability
     • 1) All probabilities have to be between 0 and 1. 0 means no chance and 1 means it has to happen
     • 2) The sum of all the probabilities has to equal one. Ex. 50/50 chance = 100
   • Sample space (S) - The set of all possible outcomes of an experiment
   • How to calculate probabilities:
     • 1) List all events in the sample space (S)
     • 2) Assign an appropriate probability to each event
     • 3) Determine which events result in the event of interest
     • 4) Add the probabilities up from step number 3
   • Random Variable - Numeral description of the outcome of an experiment
   • Probability Distribution - A formula, table, or graph that gives the probability associated with each value of the random variable
   • The power will equal the total number of questions
   • • This is the binomial probability formula
   • mean and standard deviation for binomials

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