What is the solution to this inequality?

What is the CIRCUMFERENCE of a circle with a radius of 18m?

Lyrx [107]

Answer:

the first one is 113.04m

the second one is 615.44 cm

the third one is 530.66 ft

the fourth one is 163.28 in

the fifth one is 31.4 m

the sixth one is 28.26 m

the seventh one is 314

the eightth one is 50,24

finally finished:)))

7 0

3 years ago

Consider the simple linear regression model Yi=β0+β1xi+ϵi, where ϵi's are independent N(0,σ2) random variables. Therefore, Yi is

Virty [35]

Answer:

See proof below.

Step-by-step explanation:

If we assume the following linear model:

$y = \beta_o + \beta_1 X +\epsilon$

And if we have n sets of paired observations $(x_i, y_i) , i =1,2,...,n$ the model can be written like this:

$y_i = \beta_o +\beta_1 x_i + \epsilon_i , i =1,2,...,n$

And using the least squares procedure gives to us the following least squares estimates $b_o$ for $\beta_o$ and $b_1$ for $\beta_1$ :

$b_o = \bar y - b_1 \bar x$

$b_1 = \frac{s_{xy}}{s_xx}$

Where:

$s_{xy} =\sum_{i=1}^n (x_i -\bar x) (y-\bar y)$

$s_{xx} =\sum_{i=1}^n (x_i -\bar x)^2$

Then $\beta_1$ is a random variable and the estimated value is $b_1$ . We can express this estimator like this:

$b_1 = \sum_{i=1}^n a_i y_i$

Where $a_i =\frac{(x_i -\bar x)}{s_{xx}}$ and if we see careful we notice that $\sum_{i=1}^n a_i =0$ and $\sum_{i=1}^n a_i x_i =1$

So then when we find the expected value we got:

$E(b_1) = \sum_{i=1}^n a_i E(y_i)$

$E(b_1) = \sum_{i=1}^n a_i (\beta_o +\beta_1 x_i)$

$E(b_1) = \sum_{i=1}^n a_i \beta_o + \beta_1 a_i x_i$

$E(b_1) = \beta_1 \sum_{i=1}^n a_i x_i = \beta_1$

And as we can see $b_1$ is an unbiased estimator for $\beta_1$

In order to find the variance for the estimator $b_1$ we have this:

$Var(b_1) = \sum_{i=1}^n a_i^2 Var(y_i) +\sum_i \sum_{j \neq i} a_i a_j Cov (y_i, y_j)$

And we can assume that $Cov(y_i,y_j) =0$ since the observations are assumed independent, then we have this:

$Var (b_1) =\sigma^2 \frac{\sum_{i=1}^n (x_i -\bar x)^2}{s^2_{xx}}$

And if we simplify we got:

$Var(b_1) = \frac{\sigma^2 s_{xx}}{s^2_{xx}} = \frac{\sigma^2}{s_{xx}}$

And with this we complete the proof required.

8 0

4 years ago

Please help.. ASAP Help Please do all

Semenov [28]

Answer:

1) 257

2) 24^1=24

3) 47/8(Decimal: 5.875) How to: 5/1+7/8 = 40/80+7/8 = 40 + 7 / 8 = 47/8

4)=920

5) =32.484

6) =33.444

7) = 4 : 1 How to: The GCF of 12 and 3 is 3 Divide both terms by the GCF, 3:

12 ÷ 3 = 4

3 ÷ 3 = 1 The ratio 12 : 3 can be reduced to lowest terms by dividing both terms by the GCF = 3 :

12 : 3 = 4 : 1

8) = 9 cups. How to: 2*3=6. so you multiply the other side (3) by 3 so 3*3=9 cups.

9) The second pack weighs more. How to: Since 45 ounces is 2.812 pounds (Formula

divide the mass value by 16) and 2.812 is less than 3 so second pack weighs more.

10) =26.6

Hope this helps!! If so please mark brainliest and rate/heart to help my account if it did!!

7 0

3 years ago

If the original length was 20 feet and the scaled length is 5 feet, what is the scale factor?

xenn [34]

1 to 4

Step-by-step explanation:

4 0

4 years ago

Please help it algebra 1A and i really really need help

horrorfan [7]

What do you need help with in 1A

6 0

4 years ago