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Natasha_Volkova [10]

3 years ago

7

A cylindrical well is 20 meters deep and has a diameter of 1.5 meters. Approximately how many cubic meters of soil were dug out

to make the well? (Use π = 3.14.)
11.78 cubic meters
35.33 cubic meters
121.20 cubic meters
141.30 cubic meters

2 answers:

Helen [10]3 years ago

6 0

V= $\pi r^{2} h$
$V= \pi .75(20)=35.33$

Lynna [10]3 years ago

3 0

Okay you know the drill use the volume formula for a cylinder then plug in the numbers

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A study was conducted to estimate the difference in the mean salaries of elementary school teachers from two neighboring states.

umka21 [38]

Answer:

$(28900-30300) -2.07 \sqrt{\frac{2300^2}{10} +\frac{2100^2}{14}} = -3301.70$

$(28900-30300) +2.07 \sqrt{\frac{2300^2}{10} +\frac{2100^2}{14}} = 501.698$

The confidence interval would be $-3301.70 \leq \mu \leq 501.698$ and since the confidence interval contains the value of 0 we don't have enough evidence to conclude that the difference between the two states for the salary of teachers are significantly different.

Step-by-step explanation:

We have the following info given by the problem

$\bar X_1 = 28900$ the sample mean for the salaries of teachers in Indiana

$s_1 = 2300$ the sample deviation for the salary of teachers in Indiana

$n_1 =10$ the sample size from Indiana

$\bar X_2 = 30300$ the sample mean for the salaries of teachers in Michigan

$s_2 = 2100$ the sample deviation for the salary of teachers in Michigan

$n_2 =14$ the sample size from Michigan

We want to find a confidence interval for the difference in the two means and the formula for this case is given by;

$(\bar X_1 -\bar X_2) \pm t_{\alpha/2}\sqrt{\frac{s^2_1}{n_1} +\frac{s^2_2}{n_2}}$

The degrees of freedom for this case are:

$df = n_1 +n_2 -2= 10+14-2 =22$

The confidence is 95%so then the significance is $\alpha=0.05$ and the $\alpha/2 =0.025$ , we need to find a critical value in the t distribution with 22 degrees of freedom who accumulates 0.025 of the area on each tail and we got:

$t_{\alpha/2}= 2.07$

And now replacing in the formula for the confidence interval we got:

$(28900-30300) -2.07 \sqrt{\frac{2300^2}{10} +\frac{2100^2}{14}} = -3301.70$

$(28900-30300) +2.07 \sqrt{\frac{2300^2}{10} +\frac{2100^2}{14}} = 501.698$

The confidence interval would be $-3301.70 \leq \mu \leq 501.698$ and since the confidence interval contains the value of 0 we don't have enough evidence to conclude that the difference between the two states for the salary of teachers are significantly different.

6 0

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storchak [24]

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Step-by-step explanation:

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5 0

3 years ago

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What is the answer to this?

katrin [286]

Answer:

$\huge\boxed{-28}$

Step-by-step explanation:

We can substitute the given values of $a$ , $b$ , and $c$ to find the value of this expression.

$-4 | a + b - c|$

$-4 | 3 + (-2) - (-6)|$

We know that <em>two negatives make a positive. </em>This means that $-2 - (-6)$ will be the same this as $-2+6$

$-4 | 3 + -2 + 6|$

Adding a negative is the same as subtracting a positive.

$\4 | 3-2+6|\\\\3-2+6 = 7$

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Hope this helped!

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antoniya [11.8K]

I think the answer is 59.000 B

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