STAT230 Study Guide - Midterm Guide: Decimal Mark, Blood Test

• School: University of Waterloo
• Department: Statistics
• Course: STAT230
• Professor: Changbao Wu

Document Summary

Short solutions to stat 230 test 2, feb 1, 2012: an irregular die is loaded to give the probabilities p ({1}) = 0. 2, p ({2}) = 0. 4, p ({3}) = p ({4}) = The die is rolled 8 times and results from di erent rolls are independent. [2] (a) a = 1 does not occur . P (a) = (1 0. 2)8 = 0. 88 = 0. 1678. P (b) = (1 0. 4)8 = 0. 68 = 0. 0168. [1] (b) b = 2 does not occur . [2] (c) c = neither 1 nor 2 occurs . P (c) = p (ab) = (1 0. 2 0. 4)8 = 0. 48 = 0. 00066. [2] (d) d = both 1 and 2 occur . A cheap blood test for hiv has false negative rate at 2% and false positive rate at 0. 5%. For each of the following questions, de ne the events required for the calculation and simplify the results to the 5th decimal point.