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3 years ago

HELPPP ASAP

Mathematics

1 answer:

Elena L [17]3 years ago

4 0

Answer: 680.4 square feet

Step-by-step explanation:

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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

One less than half a number is 12. What is the number

olga_2 [115]

To find this, turn the word question into an equation.
"One less than" means - 1, which is 1 being subtracted from something.
"half a number" means 1/2x, since 1/2 is half and x is unknown.
"is 12" means = 12, which is something equals 12.
Putting this in order would be 1/2x, then - 1, then = 12.
As an equation, this is 1/2x - 1 = 12.
So the equation is 1/2x - 1 = 12

Now you must find the number by solving this equation.
1/2x - 1 = 12
First, add 1 to both sides.
12 + 1 = 13
1/2x = 13
Now multiply both sides by 2.
This way, x will be isolated since 1/2x • 2 = 1x, and 1x = x.
13 • 2 = 26
x = 26
The number is 26.

6 0

2 years ago

What’s the answer for 6x + 5 = 2x -15 ?

lakkis [162]

Answer:

x=-5

Step-by-step explanation:

7 0

2 years ago

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Which of the following transformations does not preserve distance and angle measures?

Sveta_85 [38]