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AP STATISTICS Quiz-6.3b Geometric Random Variables Last 4 of Student ID____________ Period______ 1. Research suggests that about 24% of 12-year-olds in the United States can pick out the state of Colorado on a map. (a) What is the probability that you must sample exactly 5 twelve-year-olds to find the first one who can pick out Colorado on a map? P(X=5) geometpdf(.24,5)=0.0801 (b) What is the probability that you must sample 5 or more twelve-year-olds to find the first one who can pick out Colorado on a map? P(X≥5) 1-geometcdf(.24,4)=0.3336 2. Suppose that 20% of a herd of cows is infected with a particular disease. (a) What is the probability that the first diseased cow is the 3rd cow tested? P(X=3) geometpdf(.2,3)=0.128 (b) What is the probability that 4 or more cows would need to be tested until a diseased cow was found? P(X≥4) 1-geometcdf(.2,3)=0.512