Stats 250 W11 Final Exam Solutions 1 Introduction To Statistics And Data Analysis

Stats 250 W11 Final Exam Solutions Page 1 of 10 1. Number of Days on the Road - Consider the following (partial) probability distr ibution for the random variable X = the number of days for the longest car trip ove r the winter holiday. This model was presented by the national AAA organization. [11 points] Value of X = Number of days on the Road 1 2 3 4 Probability 0.10 0.30 0.25 ? a. What is the missing probability to complete the distribution for X? Final answer = _____ 0.35 _____ b. What is the expected number of days for the long est trip? Include the symbol, value, and units. E(X) = = 1(0.10) + 2(0.30) + 3(0.25) + 4(0.35) = 0.1 + 0. 6 + 0.75 + 1.4 = 2.85 _ E(X) or _ = __ 2.85 DAYS __ c. Did high gas prices keep Ann Arbor adults from h itting the road this past winter holiday? In a local survey of 100 Ann Arbor adults, the number of days spent driv ing on the road on their longest trip over the winter holiday was recorded. The data, provided below, are to be used to assess if