Repair calls. Find the mean and standard deviation of the number of repair calls the appliance shop in given Exercise should expect during an 8-hour day.
Exercise :
Repairs. The probability model below describes the number of repair calls that an appliance repair shop may receive during an hour.
|
Repair Calls
|
0
|
1
|
2
|
3
|
|
Probability
|
0.1
|
0.3
|
0.4
|
0.2
|
a) How many calls should the shop expect per hour?
b) What is the standard deviation?