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2 years ago

HELP I WILL GIVE BRAINIEST

Mathematics

1 answer:

lilavasa [31]2 years ago

5 0

Answer:

Step-by-step explanation:

common sense.

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Standardized Test Practice

Ulleksa [173]

Answer:

8x+6y=48

x+y=7

multiply bottom equation by 6:

8x+6y=48

6x+6y=42

subtract equations:

2x=6

divide 6 by 2:

x=3

therefore:

y=4

6 0

3 years ago

Read 2 more answers

Researchers are interested if a school breakfast program leads to taller children. Assume that the population of all 5 year-old

DedPeter [7]

Answer:

$39-1.96\frac{1}{\sqrt{25}}=38.608$

$39+1.96\frac{1}{\sqrt{25}}=39.392$

So on this case the 95% confidence interval would be given by (38.608;39.392)

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".

$\bar X=39$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma=1$ represent the population standard deviation

n=25 represent the sample size

Solution to the problem

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

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

The margin of error is given by:

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

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a tabel to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

And replacing we got:

$ME= 1.96 *\frac{1}{\sqrt{25}}= 0.392$

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

$39-1.96\frac{1}{\sqrt{25}}=38.608$

$39+1.96\frac{1}{\sqrt{25}}=39.392$

So on this case the 95% confidence interval would be given by (38.608;39.392)

7 0

2 years ago

Evaluate -6(x-2y) when x= -3 and y= -5 a. -42 b. 80 c. -80 d. -16

Vinil7 [7]

Simply substitute x for -3 and y for -5, creating the equation shown below:

-6 (-3 - 2(-5) )
Now that you have your values set up, now you can do the math by starting off with Multiplying -2 by -5, which will get you 10.

Now that you have the parenthesis simplified in the parenthesis, you can use the distributive property by multiplying all the numbers with -6, like so:
-6(-3+10)= 18 - 60, which simplifies to -42, in which (A) is your answer.

5 0

3 years ago

Read 2 more answers

Determine the greatest common factor of the following: 4x^2y^2, 3xy^4, 2xy^2

Mademuasel [1]

YOur greeatest common factor is 216. If you prime factor them it comes out to 216. Good luck.

7 0

3 years ago

The perimeter of a semicircle is 25.7 feet. What is the semicircle's radius? Use 3.14 for .

jarptica [38.1K]

Answer: 4.09

Step-by-step explanation: