Back to Define a random variable and graph its distribution — Problem 2 · Task Set 27
Exercises: Define a Random Variable and Graph Its Probability Distribution
Work through each section in order. A random variable X is a rule that assigns a NUMBER to each outcome in a sample space. To build its probability distribution, group the outcomes by the value of X and add the probabilities in each group; the probabilities of all values must sum to 1. Write probabilities as fractions or decimals. For explanation problems, use complete sentences. Do NOT compute expected value — that comes next lesson.
Grade 11·19 problems·~35 min·Common Core Math - HS Statistics and Probability·group·hss-md-a-1
Work through problems with immediate feedback
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Fluency Practice
Build distributions by grouping outcomes by value and summing probabilities.
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Two fair coins are tossed; each outcome HH, HT, TH, TT has probability . Let $X = $ the number of heads. The value comes only from the outcome TT. What is ? Enter your answer as a fraction.