Answer:
a) So, she can expect a 2.4 calls per hour.
b) So, the standard deviation is 0.8.
Step-by-step explanation:
We know that probability model below describes the number of repair calls that an appliance repair shop may receive during an hour.
Repair Calls 1 2 3 4
Probability 0.1 0.5 0.3 0.1
a) We calculate how many calls should the shop expect per hour.
We get:
So, she can expect a 2.4 calls per hour.
b) We calculate the standard deviation:
So, the standard deviation is 0.8.