FALL 2013 EXAM 2 SolutionsSTAT 225October 17, 2013Name:Choose your Section Time: (Circle one)7:30 Whitney10:30 Pan12:30 Allison3:30 Xiang8:30 Patrick10:30 Jeremy1:30 Mike4:30 Xiang9:30 Pan11:30 Jeremy2:30 MikeONLINEDirections1. Show your work on ALL questions. Unsupported work will NOT receive full credit.2. Decimal answers should be exact, or to exactly 4 significant digits.3. You are responsible for upholding the Honor Code of Purdue University. This includesprotecting your work from other students.4. Please write legibly. If a grader cannot read your writing, NO credit will be given.5. You are allowed the following aids:(a) a one-page 8.5“x11” handwritten cheat sheet(b) Scientific Calculator (in accordance with the syllabus)(c) Pencils or pens6. Cheat sheets with photocopied or printed information are not allowed and are subject todisciplinary actions as specified in the syllabus.7. Instructors will not interpret questions for you. If you do have questions, wait until youhave looked over the whole exam so that you can ask all your questions at one time.8. Turn off your cell phone before the exam begins.ProblemPoints PossiblePoints Earned1162839495126879Cheat Sheet1Total721

Problem 1You just got a job at a bank as a clerk.Given each scenario, identify the distribution andparameters ofX.If an approximate distribution is appropriate, name both the exact andapproximate distribution and parameters.a.(2 points)Someone was careless when filling the dispenser with deposit and withdrawalslips and put 10 deposit slips and 15 withdrawal slips in the same dispenser. A customertakes 3 slips out at random.LetXbe the number of withdrawal slips the customerremoved.

b.(2 points)The probability someone asks for a $100 bill is 0.06. LetXbe the number ofcustomers you wait on until you have someone ask for a $100 bill.

c.(2 points)Each randomly selected penny has a probability of 3/375 to be a wheat penny(minted between 1909 - 1956). You have a pile of 500 independent pennies. LetXbe thenumber of wheat pennies in your pile.