The table below shows the number of restaurants advertisement in a city directory.
1 answer:
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Answer:
E(x)=0.15
V(x)=0.3075
S(x)=0.5545
Step-by-step explanation:
The mean of a discrete variable is calculated as:
where are the values that the variable can take and
are their respective probabilities.
So, if we call x the number of defective transistors in cartons, we can calculate the mean E(x) as:
Because there are 0 defective transistor with a probability of 0.92, 1 defective transistor with a probability of 0.03, 2 defective transistors with a probability of 0.03 and 3 defective transistors with a probability of 0.01.
At the same way, the variance V(x) is calculated as:
Where
So, the variance V(x) is equal to:
Finally, the standard deviation is calculated as: