If
is the cumulative distribution function for
, then

Then the probability density function for
is
:

The
th moment of
is
![E[Y^n]=\displaystyle\int_{-\infty}^\infty y^nf_Y(y)\,\mathrm dy=\frac1{\sqrt{2\pi}}\int_0^\infty y^{n-1}e^{-\frac12(\ln y)^2}\,\mathrm dy](https://tex.z-dn.net/?f=E%5BY%5En%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20y%5Enf_Y%28y%29%5C%2C%5Cmathrm%20dy%3D%5Cfrac1%7B%5Csqrt%7B2%5Cpi%7D%7D%5Cint_0%5E%5Cinfty%20y%5E%7Bn-1%7De%5E%7B-%5Cfrac12%28%5Cln%20y%29%5E2%7D%5C%2C%5Cmathrm%20dy)
Let
, so that
and
:
![E[Y^n]=\displaystyle\frac1{\sqrt{2\pi}}\int_{-\infty}^\infty e^{nu}e^{-\frac12u^2}\,\mathrm du=\frac1{\sqrt{2\pi}}\int_{-\infty}^\infty e^{nu-\frac12u^2}\,\mathrm du](https://tex.z-dn.net/?f=E%5BY%5En%5D%3D%5Cdisplaystyle%5Cfrac1%7B%5Csqrt%7B2%5Cpi%7D%7D%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20e%5E%7Bnu%7De%5E%7B-%5Cfrac12u%5E2%7D%5C%2C%5Cmathrm%20du%3D%5Cfrac1%7B%5Csqrt%7B2%5Cpi%7D%7D%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20e%5E%7Bnu-%5Cfrac12u%5E2%7D%5C%2C%5Cmathrm%20du)
Complete the square in the exponent:

![E[Y^n]=\displaystyle\frac1{\sqrt{2\pi}}\int_{-\infty}^\infty e^{\frac12(n^2-(u-n)^2)}\,\mathrm du=\frac{e^{\frac12n^2}}{\sqrt{2\pi}}\int_{-\infty}^\infty e^{-\frac12(u-n)^2}\,\mathrm du](https://tex.z-dn.net/?f=E%5BY%5En%5D%3D%5Cdisplaystyle%5Cfrac1%7B%5Csqrt%7B2%5Cpi%7D%7D%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20e%5E%7B%5Cfrac12%28n%5E2-%28u-n%29%5E2%29%7D%5C%2C%5Cmathrm%20du%3D%5Cfrac%7Be%5E%7B%5Cfrac12n%5E2%7D%7D%7B%5Csqrt%7B2%5Cpi%7D%7D%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20e%5E%7B-%5Cfrac12%28u-n%29%5E2%7D%5C%2C%5Cmathrm%20du)
But
is exactly the PDF of a normal distribution with mean
and variance 1; in other words, the 0th moment of a random variable
:
![E[U^0]=\displaystyle\frac1{\sqrt{2\pi}}\int_{-\infty}^\infty e^{-\frac12(u-n)^2}\,\mathrm du=1](https://tex.z-dn.net/?f=E%5BU%5E0%5D%3D%5Cdisplaystyle%5Cfrac1%7B%5Csqrt%7B2%5Cpi%7D%7D%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20e%5E%7B-%5Cfrac12%28u-n%29%5E2%7D%5C%2C%5Cmathrm%20du%3D1)
so we end up with
![E[Y^n]=e^{\frac12n^2}](https://tex.z-dn.net/?f=E%5BY%5En%5D%3De%5E%7B%5Cfrac12n%5E2%7D)
The level of measurement of each given variable are:
1. Ordinal
2. Nominal
3. Ratio
4. Interval
5. Ordinal
6. Nominal
7. Ratio
8. Interval
Level of measurement is used in assigning measurement to variables depending on their attributes.
There are basically four (4) levels of measurement (see image in the attachment):
1. <u>Nominal:</u> Here, values are assigned to variables just for naming and identification sake. It is also used for categorization.
- Examples of variables that fall under the measurement are: Favorite movie, Eye Color.
<u>2. Ordinal:</u> This level of measurement show difference between variables and the direction of the difference. In order words, it shows magnitude or rank among variables.
- Examples of such variables that fall under this are: highest degree conferred, birth order among siblings in a family.
<u>3. Interval Scale:</u> this third level of measurement shows magnitude, a known equal difference between variables can be ascertain. However, this type of measurement has <em>no true zero</em> point.
- Examples of the variables that fall here include: Monthly temperatures, year of birth of college students
4. Ratio Scale: This scale of measurement has a "true zero". It also has every property of the interval scale.
- Examples are: ages of children, volume of water used.
Therefore, the level of measurement of each given variable are:
1. Ordinal
2. Nominal
3. Ratio
4. Interval
5. Ordinal
6. Nominal
7. Ratio
8. Interval
Learn more about level of measurement here:
brainly.com/question/20816026
Answer:
the side XY
Step-by-step explanation:
we know 2 angles in a triangle. but are 45 degrees.
that means the third angle Z is 180-45-45 = 90 degrees.
the side opposite of the largest angle is the longest side.
opposite of Z is the side XY.
The formula is P=Poe^rt and after 20 years the amount will be $14134.41
For Lyla, the formula used to solve the problem is P=Poe^rt
The function is P=3000 e^0.775t
After 20 years lyla amount will be P=3000e^0.775×20=14134.41$
- The exponential function is a type of mathematical function which are helpful in finding the growth or decay of population, money, price, etc that are growing or decay exponentially.
- Exponents are used in exponential functions, as the name indicates. But take note that an exponential function does not have a constant as its base and a variable as its exponent (if a function has a variable as the base and a constant as the exponent then it is a power function but not an exponential function).
- As the name implies, exponential functions employ exponents. The base and exponent of an exponential function, however, are not a constant and a variable, respectively (if a function has a variable as the base and a constant).
To learn more about exponential functions visit
brainly.com/question/11487261
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