Delivery times for shipments from a central warehouse are exponentially distributed with a mean of 2.73 days (note that times are measured continuously, not just in number of days). The standard deviation of an exponential distribution is equal to the mean of 2.73 days. A random sample of 72 shipments are selected and their shipping times are observed. Use the Central Limit Theorem to find the probability that the mean shipping time for the 72 shipments is less than 2.21 days.
Added by Stephanie H.
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73 days and the standard deviation (σ) is also 2.73 days. Second, we know that the Central Limit Theorem tells us that the distribution of sample means will be approximately normally distributed if the sample size is large enough (usually n > 30). In this case, Show more…
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