Test 1 Solution

# Test 1 Solution - the middle digit Therefore 5 4 4 9 8 7/12...

This preview shows pages 1–2. Sign up to view the full content.

STAT 230 Quiz #1 Sept 29, 2004 For all of the problems below, show your work in the space indicated! Name: I.D. No.: Section No. [_____/12] 1. Three digits are selected from 1,2, ,9 without replacement and randomly placed in a row. [4] (a) What is your sample space S for this random experiment? How many points are in S ? A possible choice of sample space S 123,213,321,. ..124,. ..789 i.e. all arrangements of 3 things taken from 9. There are 9 3 points in this S . (Note: -there may be more than one right answer) [4] (b) What is the probability that the first digit is 1 and last digit is 9? There is 1 way of choosing the number (1 for the first digit, for each of these, 1 way of choosing the number 9 for the last digit and 7 ways of choosing a number from the remaining for the middle digit. Therefore 1 7 1 9 8 7 1 72 [4] (c) What is the probability of the arrangement (odd number,even number,odd number)? There are five ways of selecting an odd number for the first digit and for each there are 4 ways of choosing an odd number for the third and 4 choices of even number for

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: the middle digit. Therefore 5 4 4 9 8 7 [_____/12] 2. Suppose A , B , C are all independent events with P A 0.3, P B 0.4, P C 0.5. [4] (a) Find P A B C The easiest way of doing this is to use part (c) and take 1 − the answer to part (c). Otherwise use the fact that A , B , C are all independent and then P A B C P A P B P C − P AB − P BC − P AC P ABC 0.7 0.4 0.5 − 0.7 0.4 − 0.4 0.5 − 0.7 0.5 0.7 0.4 0.5 [4] (b) Find P A B By independence of B , A this is P A B P A P B 0.3 0.6 0.18 [4] (c) Find the probability that none of the events A , B or C occur. This is P A B C P A P B P C 0.3 0.6 0.5 Alternative: use 1 − answer to part (a)....
View Full Document

## This note was uploaded on 10/21/2010 for the course STAT 230 taught by Professor Various during the Fall '06 term at Waterloo.

### Page1 / 2

Test 1 Solution - the middle digit Therefore 5 4 4 9 8 7/12...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online