I need to know th steps and answer

10.

Kay [80]

Answer:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.535 \leq \sigma^2 \leq 7.602$

Now we just take square root on both sides of the interval and we got:

$2.2 \leq \sigma \leq 2.8$

And the best option would be:

A. 2.2 < σ < 2.8

Step-by-step explanation:

Information provided

$\bar X=32.1$ represent the sample mean

$\mu$ population mean

s=2.4 represent the sample standard deviation

n=83 represent the sample size

Confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

The degrees of freedom are given by:

$df=n-1=83-1=82$

The Confidence is given by 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , the critical values for this case are:

$\chi^2_{\alpha/2}=62.132$

$\chi^2_{1- \alpha/2}=104.139$

And replacing into the formula for the interval we got:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.535 \leq \sigma^2 \leq 7.602$

Now we just take square root on both sides of the interval and we got:

$2.2 \leq \sigma \leq 2.8$

And the best option would be:

A. 2.2 < σ < 2.8

3 0

3 years ago

A 45 foot ladders leaning up against a building. The base of the latter is 20 feet away from the building. What is the angle of

Tatiana [17]

Answer:

The angle of elevation to the top of the building is 63.61 degrees

Step-by-step explanation:

Here, we want to calculate angle of elevation to the top of the building.

For this, we need a triangle

Please check for this in the attachment.

From the diagram, we are to calculate the angle theta.

To do this, we use trigonometric identities.

Looking at what we have, we have the hypotenuse and the adjacent.

So the trigonometric identity to use is the cosine

Mathematically Cosine theta = adjacent/hypotenuse

Thus, Cos theta = 20/45

Cos theta = 0.444444444444444

Theta = Arc cos(0.444444444444444)

Theta = 63.61 degrees

8 0

4 years ago

What is the least common denominator of 4/7, 5/14, and 4/15.

lukranit [14]

Answer:

210

Step-by-step explanation:

Rewriting input as fractions if necessary:

4/7, 5/14, 4/15

For the denominators (7, 14, 15) the least common multiple (LCM) is 210.

LCM(7, 14, 15)

Therefore, the least common denominator (LCD) is 210.

Calculations to rewrite the original inputs as equivalent fractions with the LCD:

4/7 = 4/7 × 30/30 = 120/210

5/14 = 5/14 × 15/15 = 75/210

4/15 = 4/15 × 14/14 = 56/210

3 0

3 years ago

Question and answer choices are in the SS attached!!!! Pls help me! ty!

victus00 [196]

Answer:

B

Step-by-step explanation:

It's a right triangle, so the pythagorean theorem will be used a lot.

First, find the side length on the left.

25^2 = 7^2 + y

y = 24

Now, knowing that 7 - 3 = 4 (the smaller side length), I can use this theorem again to find x.

4^2 + 24^2 = x^2

x = $\sqrt{592}$

Just need to simplify it a little farther...

592 / 16 = 37, so B must be the answer.

3 0

3 years ago

If x= 27 and y= 54 then what does w equal

beks73 [17]

The answer is 81 because 27 x 3

4 0

3 years ago

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