Suppose that a company manufactures a device that has been extensively tested in the lab to last an average of 10,000 hours of use with a standard deviation of 500 hours. The company tests samples of the product periodically to ensure quality. In one batch of the product consisting of a sample of 20 units, they reported an average time to failure of 8000 hours. How likely is it that the premature failure of this batch is due to random variation in quality?