Answer:
Get the value of each side, and then multiply the value by 2, the answer will be in square units. (this answer only applies for squares)
Notice that
for
implies that
elsewhere, since

where
is a random variable representing cable lengths according to the PDF
.
a. By definition of expectation, the mean is
![E[X]=\displaystyle\int_{-\infty}^\infty x\,f(x)\,\mathrm dx=0.1\int_{1200}^{1210}x\,\mathrm dx=1205](https://tex.z-dn.net/?f=E%5BX%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20x%5C%2Cf%28x%29%5C%2C%5Cmathrm%20dx%3D0.1%5Cint_%7B1200%7D%5E%7B1210%7Dx%5C%2C%5Cmathrm%20dx%3D1205)
The variance is
![\operatorname{Var}[X]=E[(X-E[X])^2]=E[X^2]-E[X]^2](https://tex.z-dn.net/?f=%5Coperatorname%7BVar%7D%5BX%5D%3DE%5B%28X-E%5BX%5D%29%5E2%5D%3DE%5BX%5E2%5D-E%5BX%5D%5E2)
where
![E[X^2]=\displaystyle\int_{-\infty}^\infty x^2\,f(x)\,\mathrm dx=0.1\int_{1200}^{1210}x^2\,\mathrm dx=\frac{4,356,100}3](https://tex.z-dn.net/?f=E%5BX%5E2%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20x%5E2%5C%2Cf%28x%29%5C%2C%5Cmathrm%20dx%3D0.1%5Cint_%7B1200%7D%5E%7B1210%7Dx%5E2%5C%2C%5Cmathrm%20dx%3D%5Cfrac%7B4%2C356%2C100%7D3)
so that the variance is
, making the standard deviation
.
b. The proportion of cables within specs is

Answer:
124
Step-by-step explanation:
64 • 1/2= 32
32•1/2=16
16•1/2=8
8•1/2=4
64+32+16+8+4
Answer: 0.0708
Step-by-step explanation:
Let μ denote the true average reaction time to a certain stimulus.
To determine : The P-value for a z test of H0: μ = 5 versus Ha: μ > 5.
In the given set of hypothesis , the alternative hypothesis is right -tailed , so the test is a right tailed test .
Given test statistic : a) z= 1.47
Now, the p-value for the right tailed test :
![P(z>1.47)=1-P(z\leq1.47)\ \ [\because P(Z>z)=1-P(Z\leq z)]](https://tex.z-dn.net/?f=P%28z%3E1.47%29%3D1-P%28z%5Cleq1.47%29%5C%20%5C%20%5B%5Cbecause%20P%28Z%3Ez%29%3D1-P%28Z%5Cleq%20z%29%5D)
[Using the p-value table for z]
Hence, the required P-value = 0.0708