you must identify the type of distribution represented and you must use the form
ID: 2918658 • Letter: Y
Question
you must identify the type of distribution represented and you must use the formulae associated with the distribution(s)concerned.Fifteen calculators were brought to the exam hall so that studentswho forgot their own could borrow one. Five had brand new batteries in them and were therefore rated SUPERB, sevenhad batteries in them that were a week old and those units weretherefore rated ACCEPTABLE, and the three remaining units had the same batteries in them as they had lastterm and were therefore rated DODGY.
TYPE of DISTRIBUTION: ________________________________________
a) Suppose four calculators are chosen at random from the collection. What's the probability at least one of thestudents gets a SUPERB calculator? Give answer to the nearestpercent.
b) What's the expected number of SUPERB calculators in thehands of the four students, each of whom received one of the fourchosen at random from the fifteen in the box?
Explanation / Answer
For part a start by calculating the probability that the group willcontain no superb calculators and subtract that from one to get theprobability that at least one will get a superb calculator. We have for students which tell us that we need to multiply fournumbers together. The probability that the first student doesn'tget a superb is 10/15, the probabilities that the second third andfourth don't are 9/14, 8/13, and 7/12. Multiply these to getthe probability that none get a superb calculator and subtract fromone to get answer you are looking for. For part b just multiply the fraction of superb calculators withthe number of students and this should give you the expected numberof superb calculators in the hands of the four students. (5/15 * 4)
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.