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3 years ago

Please help with this

Mathematics

2 answers:

Tpy6a [65]3 years ago

8 0

E and A :)) are the answers!

zlopas [31]3 years ago

6 0

A, B and E are correct choices

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Flow meters are installed in urban sewer systems to measure the flows through the pipes. In dry weatherconditions (no rain) the

ziro4ka [17]

Answer:

a) $\frac{(8)(30.23)^2}{20.09} \leq \sigma^2 \leq \frac{(8)(30.23)^2}{1.65}$

$363.90 \leq \sigma^2 \leq 4430.80$

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

$19.08 \leq \sigma \leq 66.56$

b) For this case we are 98% confidence that the true deviation for the population of interest is between 19.08 and 66.56

Step-by-step explanation:

423.6, 487.3, 453.2, 402.9, 483.0, 477.7, 442.3, 418.4, 459.0

Part a

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

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

On this case we need to find the sample standard deviation with the following formula:

$s=sqrt{\frac{\sum_{i=1}^8 (x_i -\bar x)^2}{n-1}}
And in order to find the sample mean we just need to use this formula:
[tex]\bar x =\frac{\sum_{i=1}^n x_i}{n}$

The sample deviation for this case is s=30.23

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=9-1=8$

The Confidence interval is 0.98 or 98%, the value of $\alpha=0.02$ and $\alpha/2 =0.01$ , and the critical values are:

$\chi^2_{\alpha/2}=20.09$

$\chi^2_{1- \alpha/2}=1.65$

And replacing into the formula for the interval we got:

$\frac{(8)(30.23)^2}{20.09} \leq \sigma^2 \leq \frac{(8)(30.23)^2}{1.65}$

$363.90 \leq \sigma^2 \leq 4430.80$

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

$19.08 \leq \sigma \leq 66.56$

Part b

For this case we are 98% confidence that the true deviation for the population of interest is between 19.08 and 66.56

4 0

3 years ago

Pls help me out it’s urgent <br> Pls don’t give out fake answers <br> WILL MARK BRAINLIEST !

pantera1 [17]

Hope I can help you!

6 0

2 years ago

PLZ HELP! Need this ASAP! Thx so much :)

saul85 [17]

they are giving you the answer AB=AC, so what that means is that the angles are congruent to each other so if angle AC=15 and angle DC=5 all the angles will be the same.

5 0

3 years ago

Pat sewed 200 tote bags in 4 hours at what rate did pat sew the tote bags

Alik [6]

Answer:

50 tote bags were sewed per hour

Step-by-step explanation:

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3 years ago

Please help :((

yanalaym [24]

Answer:

C = 2 * π * R = 2 * π * 14 = <u>87.9646 cm</u>

Step-by-step explanation:

All this means is that the perimeter, or circumference, is the distance or length around a shape or object. And the area is the amount of space inside the thing.

In today’s geometry lesson, you will review the formulas for finding the area and perimeter of basic geometric shapes.

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1 year ago