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binomial probabilty (1 Viewer)

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(if u used ur calculator can you show me how)


1. A sale representative for a tyra manufacturer claims that the company's steel-belted radial tyres last 55000km. A tyre dealer decided to check this claim by testing eight of the tyres. If 75% or more of the eight tyres he tests last at least 55000km, he will purchase tyres from the sales representative. If, in fact, 90% of the stee-belted radials produced by the manufactuer last at least 55000km, what is the probabilty that the tyre dealer will purchase tyres from the sale representative?
 
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lyounamu

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starbuckscoffee said:
(if u used ur calculator can you show me how)


1. A sale representative for a tyra manufacturer claims that the company's steel-belted radial tyres last 55000km. A tyre dealer decided to check this claim by testing eight of the tyres. If 75% or more of the eight tyres he tests last at least 55000km, he will purchase tyres from the sales representative. If, in fact, 90% of the stee-belted radials produced by the manufactuer last at least 55000km, what is the probabilty that the tyre dealer will purchase tyres from the sale representative?
75% of 8 tyres = 6 tyres
75% or more of 8 tyres = 6 or 6+ tyres

chance of lasting = 90%
chance of NOT lasting = 10%

So P(chance of purchasing) = 8C6 . (0.1)^2 . (0.9)^6 + 8C7 . (0.1)^1 . (0.9)^7 + 8C8 . (0.1)^0 . (0.9)^8
= 0.9619082...
 

polinaaa

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melanieeeetroll said:
omg you guise have done bionomials!?!

omg i feel so dumbbb
shouldn't everyone have finished all the topics now..?
 

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