(Solved):   When a survey calls residential telephone numbers at random, 20% of calls reach a live per ...

 

When a survey calls residential telephone numbers at random, 20% of calls reach a live person. Let X be the number of live calls. A. If the dialing machine makes a different number of calls, find the number of calls such that the standard deviation of the number of live calls is at most 2. (2 marks) B. If the dialing machine makes a different number of calls, find the number of calls such that the mean of non-live calls is at least 200. (2 marks)