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3 years ago

PLEASE HELP ME!!!

Mathematics

2 answers:

Elodia [21]3 years ago

7 0

Answer:

most likely a ramp because the person using a wheelchair would not be able to use stairs, and that is the only other one to get up or down levels

Cerrena [4.2K]3 years ago

5 0

Answer:

Well if they are in a wheelchair they should probably use a ramp.

Hope I Helped!!

*simplyeliza*

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Can someone help me with this problem? Thank you!

vesna_86 [32]

Answer: the answer is 180 $in^{2}$

Step-by-step explanation:

Area of a rectangle multiply length times base. 15 x 12 = 180. Hope this helps!

6 0

2 years ago

Please answer!! will give brainliest!

ella [17]

Answer:

average mean not sure please

7 0

3 years ago

Let $$X_1, X_2, ...X_n$$ be uniformly distributed on the interval 0 to a. Recall that the maximum likelihood estimator of a is $

Solnce55 [7]

Answer:

a) $\hat a = max(X_i)$

For this case the value for $\hat a$ is always smaller than the value of a, assuming $X_i \sim Unif[0,a]$ So then for this case it cannot be unbiased because an unbiased estimator satisfy this property:

$E(a) - a= 0$ and that's not our case.

b) $E(\hat a) - a= \frac{na}{n+1} - a = \frac{na -an -a}{n+1}= \frac{-a}{n+1}$

Since is a negative value we can conclude that underestimate the real value a.

$\lim_{ n \to\infty} -\frac{1}{n+1}= 0$

c) $P(Y \leq y) = P(max(X_i) \leq y) = P(X_1 \leq y, X_2 \leq y, ..., X_n\leq y)$

And assuming independence we have this:

$P(Y \leq y) = P(X_1 \leq y) P(X_2 \leq y) .... P(X_n \leq y) = [P(X_1 \leq y)]^n = (\frac{y}{a})^n$

$f_Y (Y) = n (\frac{y}{a})^{n-1} * \frac{1}{a}= \frac{n}{a^n} y^{n-1} , y \in [0,a]$

e) On this case we see that the estimator $\hat a_1$ is better than $\hat a_2$ and the reason why is because:

$V(\hat a_1) > V(\hat a_2)$

$\frac{a^2}{3n}> \frac{a^2}{n(n+2)}$

$n(n+2) = n^2 + 2n > n +2n = 3n$ and that's satisfied for n>1.

Step-by-step explanation:

Part a

For this case we are assuming $X_1, X_2 , ..., X_n \sim U(0,a)$

And we are are ssuming the following estimator:

$\hat a = max(X_i)$

$E(a) - a= 0$ and that's not our case.

Part b

For this case we assume that the estimator is given by:

$E(\hat a) = \frac{na}{n+1}$

And using the definition of bias we have this:

$E(\hat a) - a= \frac{na}{n+1} - a = \frac{na -an -a}{n+1}= \frac{-a}{n+1}$

Since is a negative value we can conclude that underestimate the real value a.

And when we take the limit when n tend to infinity we got that the bias tend to 0.

$\lim_{ n \to\infty} -\frac{1}{n+1}= 0$

Part c

For this case we the followng random variable $Y = max (X_i)$ and we can find the cumulative distribution function like this:

$P(Y \leq y) = P(max(X_i) \leq y) = P(X_1 \leq y, X_2 \leq y, ..., X_n\leq y)$

And assuming independence we have this:

$P(Y \leq y) = P(X_1 \leq y) P(X_2 \leq y) .... P(X_n \leq y) = [P(X_1 \leq y)]^n = (\frac{y}{a})^n$

Since all the random variables have the same distribution.

Now we can find the density function derivating the distribution function like this:

$f_Y (Y) = n (\frac{y}{a})^{n-1} * \frac{1}{a}= \frac{n}{a^n} y^{n-1} , y \in [0,a]$

Now we can find the expected value for the random variable Y and we got this:

$E(Y) = \int_{0}^a \frac{n}{a^n} y^n dy = \frac{n}{a^n} \frac{a^{n+1}}{n+1}= \frac{an}{n+1}$

And the bias is given by:

$E(Y)-a=\frac{an}{n+1} -a=\frac{an-an-a}{n+1}= -\frac{a}{n+1}$

And again since the bias is not 0 we have a biased estimator.

Part e

For this case we have two estimators with the following variances:

$V(\hat a_1) = \frac{a^2}{3n}$

$V(\hat a_2) = \frac{a^2}{n(n+2)}$

On this case we see that the estimator $\hat a_1$ is better than $\hat a_2$ and the reason why is because:

$V(\hat a_1) > V(\hat a_2)$

$\frac{a^2}{3n}> \frac{a^2}{n(n+2)}$

$n(n+2) = n^2 + 2n > n +2n = 3n$ and that's satisfied for n>1.

8 0

4 years ago

Two trains start from Fort Worth traveling at the same speed. The trip for Train W takes 20 hours, while the trip for Train Z ta

MrMuchimi

Answer:

The equation that best models this situation is :

b. $\frac{x}{20}=\frac{x+400}{25}$

Distance traveled by Train W = 1600 miles

Distance traveled by Train Z = 2,000 miles

Step-by-step explanation:

Given:

Time taken for Train W to complete a trip = 20 hours

Time taken for Train Z to complete a trip = 25 hours

The city Train Z is traveling to is 400 miles farther away than the city Train W is traveling to.

both trains have same speeds and start from same location.

To find the distance in total each train travels.

Solution:

Let length of the trip of Train W be = $x$ miles

Speed of Train W can be given as :

⇒ $\frac{Distance}{Time}$

⇒ $\frac{x}{20}\ miles/h$

So, the length of the trip of Train Z will be = $(x+400)$ miles

Speed of Train Z can be given as :

⇒ $\frac{Distance}{Time}$

⇒ $\frac{x+400}{25}\ miles/h$

Since the speeds are same, so the equation to find $x$ can be given as:

⇒ $\frac{x}{20}=\frac{x+400}{25}$

Solving for $x$

Multiplying both sides by 100 to remove fractions.

⇒ $100\times \frac{x}{20}=100\times \frac{x+400}{25}$

⇒ $5x=4(x+400)$

Using distribution.

⇒ $5x=4x+1600$

Subtracting both sides by $4x$

⇒ $5x-4x=4x-4x+1600$

⇒ $x=1600$

Thus, Distance traveled by Train W = 1600 miles

Distance traveled by Train Z = $1600+400$ = 2,000 miles

3 0

3 years ago

When the distributive property is applied, which number completes the statement correctly?

maxonik [38]

-7, because you distribute it to both -4 and 3.2, which means you're multiplying it to both.

7 0

3 years ago