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2 years ago

The Park Protectors is a group of elementary students and teachers from

Mathematics

2 answers:

tino4ka555 [31]2 years ago

7 0

Answer:

Step-by-step explanation:87

ExtremeBDS [4]2 years ago

7 0

Answer: 70

Step-by-step explanation: i dont really have an explanation but its the right answer

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Someone help me with the steps please

Vesna [10]

Answer:

Let $u=3x^2-3x$

Solution: $\frac{1}{6} \sqrt{3x^2-3x}+C$

Step-by-step explanation:

See attached for step-by-step

8 0

2 years ago

Let X1,X2......X7 denote a random sample from a population having mean μ and variance σ. Consider the following estimators of μ:

Viefleur [7K]

Answer:

a) In order to check if an estimator is unbiased we need to check this condition:

$E(\theta) = \mu$

And we can find the expected value of each estimator like this:

$E(\theta_1 ) = \frac{1}{7} E(X_1 +X_2 +... +X_7) = \frac{1}{7} [E(X_1) +E(X_2) +....+E(X_7)]= \frac{1}{7} 7\mu= \mu$

So then we conclude that $\theta_1$ is unbiased.

For the second estimator we have this:

$E(\theta_2) = \frac{1}{2} [2E(X_1) -E(X_3) +E(X_5)]=\frac{1}{2} [2\mu -\mu +\mu] = \frac{1}{2} [2\mu]= \mu$

And then we conclude that $\theta_2$ is unbiaed too.

b) For this case first we need to find the variance of each estimator:

$Var(\theta_1) = \frac{1}{49} (Var(X_1) +...+Var(X_7))= \frac{1}{49} (7\sigma^2) = \frac{\sigma^2}{7}$

And for the second estimator we have this:

$Var(\theta_2) = \frac{1}{4} (4\sigma^2 -\sigma^2 +\sigma^2)= \frac{1}{4} (4\sigma^2)= \sigma^2$

And the relative efficiency is given by:

$RE= \frac{Var(\theta_1)}{Var(\theta_2)}=\frac{\frac{\sigma^2}{7}}{\sigma^2}= \frac{1}{7}$

Step-by-step explanation:

For this case we assume that we have a random sample given by: $X_1, X_2,....,X_7$ and each $X_i \sim N (\mu, \sigma)$

Part a

In order to check if an estimator is unbiased we need to check this condition:

$E(\theta) = \mu$

And we can find the expected value of each estimator like this:

$E(\theta_1 ) = \frac{1}{7} E(X_1 +X_2 +... +X_7) = \frac{1}{7} [E(X_1) +E(X_2) +....+E(X_7)]= \frac{1}{7} 7\mu= \mu$

So then we conclude that $\theta_1$ is unbiased.

For the second estimator we have this:

$E(\theta_2) = \frac{1}{2} [2E(X_1) -E(X_3) +E(X_5)]=\frac{1}{2} [2\mu -\mu +\mu] = \frac{1}{2} [2\mu]= \mu$

And then we conclude that $\theta_2$ is unbiaed too.

Part b

For this case first we need to find the variance of each estimator:

$Var(\theta_1) = \frac{1}{49} (Var(X_1) +...+Var(X_7))= \frac{1}{49} (7\sigma^2) = \frac{\sigma^2}{7}$

And for the second estimator we have this:

$Var(\theta_2) = \frac{1}{4} (4\sigma^2 -\sigma^2 +\sigma^2)= \frac{1}{4} (4\sigma^2)= \sigma^2$

And the relative efficiency is given by:

$RE= \frac{Var(\theta_1)}{Var(\theta_2)}=\frac{\frac{\sigma^2}{7}}{\sigma^2}= \frac{1}{7}$

5 0

3 years ago

You only want to buy photos in sizes that are similar rectangles for your new gallery wall in your home. Which size photos shoul

Svet_ta [14]

You'd want to buy the 4 by 5 and the 11 by 14 because if you times 4 by 3 and 5 by 3, the answer would be 12 by 15 which is the closet or the most similar pair

4 0

2 years ago

A ferry traveled 1/6 of the distance between two ports in

wel

First, we determine the speed of the ferry by dividing the distance by the time it took to cover that certain distance.

speed = (1/6) / (3/7)

speed = 7/18

Then, the distance it will travel for an hour is calculated through the procedure below.

distance = (7/18hour) x (1 hour)

distance = 7/18

Therefore, after an hour, the ferry will be able to travel 7/18 of the distance between two ports.

7 0

2 years ago

What is the volume of a hemisphere with a diameter of 60.9 in, rounded to the

Oksanka [162]

78 I think because you have to see the other 2 numbers

8 0

2 years ago

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