University:
California State University, Northridge
Course:
MATH 340 | Introduction to Probability and Statistics
Academic year:

2015
Views:

490

Pages:

2
Author:

vlc1178z8h

MATH 340, Quiz 7 Name: (print) ------=S=---_M __ ... _�_uJ_·_� ______ _ Each problem is worth 2 points. Show all your work. 1. The probability density function of X, the lifetime of a certain type of elctronic device (measured in hours), is given by (a) Find P(X > 20). f(x) = { �' 0, > 10 otherwise. X (b) Find the cumulative distribution function of X. eo-,J 'P(x>�),,. J o- :)a • 10 "f.'1- J 'f. Gl f 2. A point is chosen at random on a line segment of length 0 L. Interpret this statement, and find the probability that the ratio of the shorter to the longer segment is less than ¼. t--f { -----ti o +t-' �L- r( L X tI I Please turn over... (O