PLEASE ANSWER FOR POINTS: Which diagram best connects a central Asian country with an important event from its history? A: Armen
1 answer:
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Answer:
In order to find the variance we need to find first the second moment given by:
And replacing we got:
The variance is calculated with this formula:
And the standard deviation is just the square root of the variance and we got:
Step-by-step explanation:
Previous concepts
The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.
The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).
Solution to the problem
LEt X the random variable who represent the number of defective transistors. For this case we have the following probability distribution for X
X 0 1 2 3
P(X) 0.92 0.03 0.03 0.02
We can calculate the expected value with the following formula:
And replacing we got:
In order to find the variance we need to find first the second moment given by:
And replacing we got:
The variance is calculated with this formula:
And the standard deviation is just the square root of the variance and we got:
As the problem states, to solve this, we are going to use the equation 
where
is the loudness in dB
is the intensity of a sound
<span>is the minimum intensity detectable by the human ear
</span>
We know for our problem that
; we also now that the minimum intensity detectable by the human ear is 
, so 
. Lets replace those values in our equation to find :
Qe can conclude that since the explosion is under 100dB, it does not violates the regulation of the town. We used tow physical values to calculate the answer: the intensity of the sound of the explosion,
, and the minimum intensity detectable by the human ear 
.
where
</span>
We know for our problem that
Qe can conclude that since the explosion is under 100dB, it does not violates the regulation of the town. We used tow physical values to calculate the answer: the intensity of the sound of the explosion,