(Solution Download) The probability mass function of the number of calls taken

The probability mass function of the number of calls taken by a switchboard within 1 minute is given in Figure 2.77.

(a) Compute and sketch the cumulative distribution function of the number of calls taken within a minute.
(b) What is the expected number of calls taken within a minute?
(c) What is the variance of the number of calls taken within a minute?
(d) If the numbers of calls taken in two different minutes are independent, what are the expectation and variance of the number of calls taken within one hour?

 

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