TU Wien:Statistik und Wahrscheinlichkeitstheorie UE (Bura)/Übungen 2019W/1.6
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- Computer reliability
A campus bookstore sells two types of computers: laptops and desctops. In the last semester it sold 56% laptops and 44% desktops. Reliability rates for the two types of machines are quite different. In the first year, 5% of desktops require service, while 15% of laptops have problems requiring service.
- (a) Sketch a probability tree for this situation.
- (b) What percentage of computers sold by the bookstore last semester required service?
- (c) Given that a computer required service, what is the probability that it was a laptop?
Lösungsvorschlag von Gittenburg[Bearbeiten | Quelltext bearbeiten]
--Gittenburg 09:41, 15. Okt. 2019 (CEST) a)
computer 0.56/ \0.44 laptop desktop 0.15/ \0.85 0.95/ \0.05 service no service service
b) 0.56 * 0.15 + 0.44*0.05 = 0.106
c) (0.15 * 0.56)/(0.15 * 0.56 + 0.44*0.05) ~= 0.79