Find the expected value and standard deviation of a random variable.
-A fast food restaurant just leased a new freezer and food fryer for three years. The
Service contract for the freezer offers unlimited repairs for a fee of $125 a year plus a $35
Service charge for each repair needed. The restaurant's research indicates that during a
Given year 80% of these freezers need no repairs, 11% needed to be serviced once, 5%
Twice, 4% three times, and none required more than three repairs. The standard deviation
Of the number of repairs for this freezer per year is
A) 0.72 repairs.
B) $\text { B. } 0.512 \text { repairs } { } ^ { 2 } \text {. }$
C)C 1.25 repairs.
D) 2.5 repairs2.
E) 0.33 repairs.

Question

Quizplus · Accepted Answer

The standard deviation of the number of repairs per year is calculated using the probabilities and the number of repairs. The variance is calculated as $\sum (x_i - \mu)^2 \cdot P(x_i)$, where $\mu$ is the expected value. The square root of the variance gives the standard deviation, which is approximately 0.72 repairs.

Find the Expected Value and Standard Deviation of a Random B. 0.512 repairs 2. \text { B. } 0.512 \text { repairs } { } ^ { 2 } \text {. } B. 0.512 repairs 2.

Find the Expected Value and Standard Deviation of a Random $\text { B. } 0.512 \text { repairs } { } ^ { 2 } \text {. }$