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3 years ago

PLEASE HELP ME 20 POINTS + BRAINLIEST

Mathematics

2 answers:

nataly862011 [7]3 years ago

8 0

9514 1404 393

Answer:

(b) 36.56 ft

Step-by-step explanation:

The perimeter is the total of the circumference of a 4 ft circle and two lengths that are 12 ft.

The circumference is given by ...

C = πd

C = (3.14)(4 ft) = 12.56 ft

Adding the 24 ft of straight sections, we find the total perimeter to be ...

P = 12 + 12 + 12.56 = 36.56 . . . feet

xxTIMURxx [149]3 years ago

3 0

Answer:

OPTION B

Step-by-step explanation:

SEE IMAGE FOR ANSWER.

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The volume of a fish tank is 30 ft.³ if the Density is 0.3 how many fishes are in the tank

marta [7]

The answer is 9 fish.

The density (d) is the number of units(n) per volume (V):
d = n/V We know: d = 0.3 fish/ft³. V = 30 ft³ n = ? d = n/V n = d * V n = 0.3 fish/ft³ * 30 ft³ n = 9 fish

5 0

3 years ago

Six measurements were made of the magnesium ion concentration (in parts per million, or ppm) in a city's municipal water supply,

myrzilka [38]

Answer:

$163.83-4.03\frac{20.094}{\sqrt{6}}=130.77$

$163.83+4.03\frac{20.094}{\sqrt{6}}=196.89$

So on this case the 99% confidence interval would be given by (130.77;196.89)

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Data: 175 177 175 180 138 138

We can calculate the mean and the deviation from these data with the following formulas:

$\bar X= \frac{\sum_{i=1}^n x_i}{n}$

$s=\sqrt{\frac{\sum_{i=1}^n (x_i -\bar X)^2}{n-1}}$

$\bar X=163.83$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=20.093 represent the sample standard deviation

n=6 represent the sample size

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=6-1=5$

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,5)".And we see that $t_{\alpha/2}=4.03$

Now we have everything in order to replace into formula (1):

$163.83-4.03\frac{20.094}{\sqrt{6}}=130.77$

$163.83+4.03\frac{20.094}{\sqrt{6}}=196.89$

So on this case the 99% confidence interval would be given by (130.77;196.89)

7 0

3 years ago

How many ways can you arrange your 3 statistics books, 2 math books, and 1 computer science book on your bookshelf if (a) the bo

katrin [286]

Answer:

720 different ways.

Step-by-step explanation:

Permutation has to do with arrangement. For example, in order to arrange 'n' objects in any order, this can only be done in n! ways since there is no condition or restriction on how to arrange the objects.

n! = n(n-1)(n-2)... (n-r)!

If there are 3 statistics books, 2 math books, and 1 computer science book on your bookshelf, the total number of books altogether is 3 + 2 + 1 = 6 books.

The number of ways that 6 books can be arranged in any order is 6!.

6! = 6(6-1)(6-2)(6-3)(6-4)(6-5)

6! = 6*5*4*3*2*1

6! = 120*6

6!= 720 different ways.

Hence, the books on your shelf can be arranged in 720 different ways.

3 0

3 years ago

A circle with radius 5 has a sector with a central angle of 9/10 pi

Solnce55 [7]

Answer:

35.33