
This distribution has expectation
![E[X]=\displaystyle\int_{-\infty}^\infty xf_X(x)\,\mathrm dx=\int_1^\infty\frac3{x^3}\,\mathrm dx=\frac32](https://tex.z-dn.net/?f=E%5BX%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20xf_X%28x%29%5C%2C%5Cmathrm%20dx%3D%5Cint_1%5E%5Cinfty%5Cfrac3%7Bx%5E3%7D%5C%2C%5Cmathrm%20dx%3D%5Cfrac32)
a. The probability that
falls below the average/expectation is

b. Denote by
the largest of the three claims
. Then the density of this maximum order statistic is

where
is the distribution function for
. This is given by

So we have

and the expectation is
![E[X_{(3)}]=\displaystyle\int_{-\infty}^\infty xf_{X_{(3)}}(x)\,\mathrm dx=\int_1^\infty\frac9{x^3}\left(1-\frac1{x^3}\right)^2\,\mathrm dx=\frac{81}{40}=\boxed{2.025}](https://tex.z-dn.net/?f=E%5BX_%7B%283%29%7D%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20xf_%7BX_%7B%283%29%7D%7D%28x%29%5C%2C%5Cmathrm%20dx%3D%5Cint_1%5E%5Cinfty%5Cfrac9%7Bx%5E3%7D%5Cleft%281-%5Cfrac1%7Bx%5E3%7D%5Cright%29%5E2%5C%2C%5Cmathrm%20dx%3D%5Cfrac%7B81%7D%7B40%7D%3D%5Cboxed%7B2.025%7D)
c. Denote by
the smallest of the three claims.
has density

so the expectation is
![E[X_{(1)}]=\displaystyle\int_{-\infty}^\infty xf_{X_{(1)}}(x)\,\mathrm dx=\int_1^\infty\frac9{x^9}\,\mathrm dx=\frac98=\boxed{1.125}](https://tex.z-dn.net/?f=E%5BX_%7B%281%29%7D%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20xf_%7BX_%7B%281%29%7D%7D%28x%29%5C%2C%5Cmathrm%20dx%3D%5Cint_1%5E%5Cinfty%5Cfrac9%7Bx%5E9%7D%5C%2C%5Cmathrm%20dx%3D%5Cfrac98%3D%5Cboxed%7B1.125%7D)
Answer: 5,4
Step-by-step explanation:
I did the test
Given:
Total number of calculators in a box = 10
Defective calculators in the box = 1
To find:
The number of ways in which four calculators be selected and one of the four calculator is defective.
Solution:
We have,
Total calculators = 10
Defective calculators = 1
Then, Non-defective calculator = 10-1 = 9
Out of 4 selected calculators 1 should be defective. So, 3 calculators are selected from 9 non-defective calculators and 1 is selected from the defective calculator.






Therefore, the four calculators can be selected in 84 ways.
Answer:
c = 49°
Step-by-step explanation:
Inside of the triangle angles:
- c–18°
- c–16°
- 180°-(c+15) → -c+165
these angles sum up to total 180° angle
-c+165+c-16°+c–18° = 180
c +131 = 180
c = 180° - 131°
c = 49°
Answer:
38°
Step-by-step explanation:
EFGH is an isosceles trapezoid (a trapezoid with two congruent legs is isosceles)
∠HGF=70° (base angles of an isosceles trapezoid are congruent)
∠EGH=32° (angles in a triangle add to 180°)
∠FGE=38° (angle subtraction postulate)