The number of arrivals per minute at a bank located in the central business district of a large city was recorded over a period of 200 minutes, with the following results:
Arrivals Frequency
0...............................14
1...............................31
2...............................47
3...............................41
4...............................29
5...............................21
6...............................10
7.................................5
8.................................2
a. Compute the expected number of arrivals per minute.
b. Compute the standard deviation.