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3 years ago

Fin math today PLEASE

Mathematics

1 answer:

ollegr [7]3 years ago

4 0

Answer:

1) Area:

So to find area follow the formula

a=πr^2

a=area

π= pi or 3.14 in this situation

r= radius

So we have only the diameter.

To in Find the radius you can divide the diameter by 2 and get the radius which is

84/2=42

3.14*42^2=

Area: 5538.96 ft^2

2) Circumference:

To find the circumfeence you just multiply the diameter by π or in this case 3.14.

c=πd

c= circumference

d= diameters

3.14*84=

Circumfrence: 263.76 ft

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A soccer ball manufacturer wants to estimate the mean circumference of soccer balls within 0.1 in. Determine the minimum sample

leva [86]

Answer:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (2)

The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025,0,1)", and we got $z_{\alpha/2}=1.96$ , replacing into formula (2) we got:

$n=(\frac{1.96(0.25)}{0.1})^2 =24.01$

So the answer for this case would be n=25 rounded up to the nearest integer

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".

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

$\mu$ population mean (variable of interest)

$\sigma=0.25$ represent the population standard deviation

n represent the sample size (variable of interest)

Solution to the problem

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

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

And on this case we have that ME =0.1 and we are interested in order to find the value of n, if we solve n from equation (1) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (2)

$n=(\frac{1.96(0.25)}{0.1})^2 =24.01$

So the answer for this case would be n=25 rounded up to the nearest integer

8 0

4 years ago

Solve using the substitution method. x + 2y = 9 x + 3y = 13

Rasek [7]

x + 2y = 9

x + 3y = 13

____________________________________________________________

Solve for x in the first equation. Subtract 2y from both sides.

x = 9 - 2y

____________________________________________________________

Plug x into the second equation.

(9 - 2y) + 3y = 13

Combine like terms.

9 + y = 13

Subtract 9 from both sides.

y = 4

____________________________________________________________

Plug y back into the first equation.

x + 2(4) = 9

x + 8 = 9

Subtract 8 from both sides.

x = 1

____________________________________________________________

x = 1

y = 4

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3 years ago

The table lists the number of pitches seen by a player in 6 games. What is the mean of the data

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olga2289 [7]

let M be Manuel's age

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3 years ago

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How to write the fraction 6/6 as a sum of fractions three different ways

Aleks [24]

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