Unformatted text preview: with mean 50 minutes and standard deviation 10 minutes. When should the test be terminated if we wish to allow sufficient time for 95% of the students to complete the test? 4. Suppose the length of time (Y) necessary to fix a copier machine follows an exponential distribution with mean 2 hours. The formula C=10+5Y + 2Y 2 relates the repair cost C and Y. Find the mean and variance of C. 5. If ) 1 , 1 ( ~ Beta Y , show Y ~ Uniform(0,1). That is, the uniform distribution over interval (0,1) is a special case of a beta distribution. 6. If a random variable Y has the following density: +∞ < < ∞=y ke y f y , ) ( 2 / 2 a. Find k such that f(y) is a valid pdf. b. Find the momentgenerating function of Y. c. Find E[Y] and Var(Y) by moments....
View
Full Document
 Fall '07
 lan
 Normal Distribution, Variance, Probability theory, probability density function, cable line

Click to edit the document details