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3 years ago

Question 8 A scuba diver descends 13 feet and then another 20 feet. What is his final position?

Mathematics

2 answers:

OverLord2011 [107]3 years ago

6 0

Answer:

33 feet

Step-by-step explanation:

20 + 13 add 20 and 13

33 feet

xz_007 [3.2K]3 years ago

4 0

The answer would be -33

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Two skaters are racing toward the finish line of a race. The first skater has a 40 m lead and is traveling at a rate of 12 m/s.

ivanzaharov [21]

The second skater wont pass him, he is ahead and they are going the same speed

3 0

3 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

Rewrite the quadratic function below in Standard Form. y = (x - 4) (x + 3)

Damm [24]

the standard form of a quadratic formula is

y = ax^2 + bx + c

in this case you will solve using foil method

(× - 4)(x + 3)

(x × x) +( x × 3 )(- 4 × x) ( -4)× 3))

x^2 + 3x - 4x -12

x^2 - x - 12

therefore

y = x^2- x - 12

5 0

2 years ago

Rice is being poured into a cylindrical container with radius 4.5 inches so

12345 [234]

asked:the istant of height is the same as the radius

given facts:cylindrical container with radius 3.5 inches height of rice increasing 0.5 inches per second

solve hidden given:(4.5+o.5+2)

what operation to be used: addition and subtraction

solve+4.5+05+2=6.0

chec: 6.0-4.5=1.5

8 0

2 years ago

I need answer to both of the questions please someone!! 20points

diamong [38]

Answer:

Step-by-step explanation:

x+62=90 degree (being perpendicular)

x=90-62

x=28 degree

x+25=90 (being perpendicular)

x=90-25

x=65 degree

8 0

3 years ago

Read 2 more answers