Consider a population of lightbulbs with mean failure time = 50 days and standard deviation of failure times = 20 days. According to our simulation, even if the failure time follows an exponential distribution, its sample mean approaches a normal distriution. Therefore, if you take a sample of 100 lightbulbs, what are the chances the mean failure time of your sample will be less than 48 days? Enter your answer to 5 decimal places