Problem

For the given probability density function, over the given interval, find the mean, the variance, and the standard deviation.
\[
f(x)=4,[2.25,2.50]
\]
A. $\mu=2.500 ; \sigma^{2}=0.0048 ; \sigma=0.069$
B. $\mu=2.375 ; \sigma^{2}=0.021 ; \sigma=0.144$
C. $\mu=2.375 ; \sigma^{2}=0.0052 ; \sigma=0.072$
D. $\mu=2.500 ; \sigma^{2}=0.0049 ; \sigma=0.070$

Answer

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Answer

Final Answer: The mean is \(\boxed{2.375}\), the variance is \(\boxed{0.0052}\), and the standard deviation is \(\boxed{0.072}\). Therefore, the correct answer is C. \(\mu=2.375 ; \sigma^{2}=0.0052 ; \sigma=0.072\).

Steps

Step 1 :The given probability density function is a constant function \(f(x) = 4\) over the interval [2.25, 2.50]. This is a uniform distribution.

Step 2 :The mean (or expected value) of a probability density function (pdf) is given by the integral of \(x*f(x)\) over the given interval. For a uniform distribution, the mean is simply the midpoint of the interval. So, \(\mu = 2.375\).

Step 3 :The variance is given by the integral of \((x - \mu)^2 * f(x)\) over the given interval. Calculating this gives \(\sigma^{2} = 0.0052\).

Step 4 :The standard deviation is the square root of the variance. So, \(\sigma = \sqrt{0.0052} = 0.072\).

Step 5 :Final Answer: The mean is \(\boxed{2.375}\), the variance is \(\boxed{0.0052}\), and the standard deviation is \(\boxed{0.072}\). Therefore, the correct answer is C. \(\mu=2.375 ; \sigma^{2}=0.0052 ; \sigma=0.072\).

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