Sure Stone Tire Company has established that the useful life of a particular brand of its automobile tires is normally distributed with a mean of 40,000 kilometres and a standard deviation of 5000 kilometres.What is the probability that a randomly selected tire of this brand has a life of at least 50,000 kilometres?
A)0.0228
B)0.9772
C)0.5000
D)0.4772
E)1.0000

Question

Quizplus · Accepted Answer

The Z-score for 50,000 km is (50,000 - 40,000) / 5,000 = 2. The probability of a Z-score being at least 2 is 1 - 0.9772 = 0.0228.

Sure Stone Tire Company Has Established That the Useful Life