Question

A type of lightbulb is labeled as having an average lifetime of 1000 hours.


(a)A type of lightbulb is labeled as having an average lifetime of 1000 hours. It's reasonable to model the probability of failure of these bulbs by an exponential density function with mean μ = 1000. 

(i) Use this model to find the probability that a bulb fails within the first 500 hours (Round your answer to three decimal places.) 

(ii) Use this model to find the probability that a bulb bums for more than 700 hours. 


(b) What is the median lifetime of these lightbulbs? (Round your answer to one decimal place.)

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