The Probability Model Below Describes the Number of Repair Calls That an Appliance Repair Shop May Receive?
Ray asked:
The probability model below describes the number of repair calls that an appliance repair shop may receive during one hour.
Repair calls 0 1 2 3
Probability 0.1 0.3 0.4 0.2
The probability model below describes the number of repair calls that an appliance repair shop may receive during one 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? Explain your answer..
b) What is the standard deviation?
Jesus
Tagged with: Appliance Repair • Repair Appliance • Standard Deviation
Filed under: Appliance Stuff
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The expected number of calls per hour is the mean value. It is obtained as ‘sum of xp’. Here it is 0*0.1+1*0.3+2*0.4+3*0.2 = 1.7 (the symbol * indicates multiplication). Thus an average of 1.7 calls may be expected during one hour.
The standard deviation will be E(x^2) – (E(x))^2. This can be calculated as 0^2*0.1 +1^2*0.3+2^2*0.4+3^2*0.2 – 1.7^2 = 0+0.3+4*0.4+9*0.2 – 1.7^2 =3.7 – 2,89 =0.81.