15 015 0 1 1 08610139 0 comments on grading on

Info iconThis preview shows page 1. Sign up to view the full content.

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

Unformatted text preview: SUM 0.860708 P(Fatality’) = 0.861 P(Fatality) = 1 – 0.861 = 0.139 Alternative solution −1 New mean occurrence rate λnew = 0.05 year λnewt = 0.05 ⋅ 3 = 0.15 P(one or more accidents in three years)=1 ­P(no accidents in three years) e −0.15 ⋅ 0.15 0 1− = 1 − 0.861=0.139 = 0! Comments on Grading on #1 a) This question is quite straight forward. Most students got it right. one point is off for wrong calculation. b) If you used the method in hint (i), the rubric is as follows: 8 points for recognition of total probability, 2 points for starting the number of accident from zero (theoretically, the range of X is 0 to infinity), 2 points for binomial distribution of P(0 fatality|X accidents), 2 points for poisson distribution of P(X accidents), 2 points for making the complement right P(one or more fatality)=1 ­P(0 fatality) and 1 point for right calculation. Some students...
View Full Document

Ask a homework question - tutors are online