1. AP STATISTICS Section 7.1 Random Variables

2. Objective: To be able to recognize discrete and continuous random variables and calculate probabilities using them. A Random Variable is a variable whose value is a numerical outcome of a random event. Denoted using capital letters: X, Y, … Ex. X = sum of 2 dice A discrete random variable has a countable number of possible outcomes. A probability distribution is a table that assigns probabilities to outcomes of a discrete random variable.

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4. Ex. Create the probability distribution for the random variable X where X = the sum of two dice. Then answer the following questions. Find P(X=7 or 11) = Find P(X = 2 or 3 or 12)= The best way to display a probability distribution is through the use of a __________________________.

5. Ex. Create a probability distribution for the random variable X where X = the number of times a head is observed when a coin is tossed 3 times. REVIEW DENSITY CURVES: 1. 2. Z-SCORES:

6. A continuous random variable takes on all values of that random variable in an interval of numbers. The probability distribution of a continuous random variable is described by a density curve. The area under the curve represents the probability of the said event occurring. Continuous random variables are measured while discrete are counted. Ex. Let X~U(0,2) a. Sketch this density curve.