question archive The life of a nickel-cadmium battery produced by a manufacturer is normally distributed with a mean of 20 hours and a standard deviation of 4 hours
The life of a nickel-cadmium battery produced by a manufacturer is normally distributed with a mean of 20 hours and a standard deviation of 4 hours
Subject:StatisticsPrice: Bought3
The life of a nickel-cadmium battery produced by a manufacturer is normally distributed with a mean of 20 hours and a standard deviation of 4 hours.(a) What proportion of batteries have a life of less than 15 hours?(b) The manufacturer is considering a warranty for the battery. How many hours of use should the warranty cover so that 5% of the batteries have to be replaced?(c) Suppose that a battery with life of less than 15 hours is considered to be defective. If 8 batteries are selected at random from a large batch, what is the probability that at most 2 batteries are defective?
