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nevsk [136]
3 years ago
12

PLZ HELPPPPP!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mathematics
1 answer:
stepan [7]3 years ago
5 0

1. One face is 5.1*2.5=12.75 un^2, one is 8.5*2.5=21.25, one is 6.8*2.5=17, and two are 1/2*6.8*5.1, so both are 34.68. Total is 85.68, rounded to 85.7 cm^2. (C)

2. The area of the circles is 2(π*2^2), which is about 25.1. The rectangle's area can be found as 2π*2*3, which is about 37.7. The total is rounded to 62.8 m^2 (D)

3. Rectangular faces: 3.6*1.8=6.48, 8.5*1.8=15.3, 7.7*1.8=13.86

Triangles: 2(1/2(3.6*7.7))=27.72

Total: 63.36, round to 63.4 km^2 (B)

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Step-by-step explanation:

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ILL GIVE U BRAINLYIST IF U ANSWER. Find the solution to the system of equations below (you can do this by substitution or elimin
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Elimination:

-4x+y=6

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(the y cancelled out so its 0) x =27

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Hope this helped :)

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3 years ago
Four woman must cross a bridge over a deep canyon. It is a enemy territory. The must cross in the middle of the night. A lantern
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The 5 and 10 min cross. 10 
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3 years ago
A study was conducted to measure the effectiveness of hypnotism in reducing pain. The measurements are centimeters on a pain sca
saul85 [17]

Answer:

The 95% confidence interval for the difference would be given by (-1.776;0.376)

We are 95% confidence that the true mean difference is between -1.776 \leq \mu_d \leq 0.376. Since the confidence interval contains the value 0, we don't have enough evidence to conclude that hypnotism appear to be effective in reducing pain.

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".

Let put some notation  

x=test value before , y = test value after

x: 6.4 2.6 7.7 10.5 11.7 5.8 4.3 2.8

y: 6.7 2.4 7.4 8.1 8.6 6.4 3.9 2.7

The differences defined as d_i = y_i -x_i and we got:

d: 0.3, -0.2, -0.3, -2.4, -3.1, 0.6, -0.4, -0.1

We can calculate the mean and the deviation for the sample with the following formulas:

\bar d=\frac{\sum_{i=1}^n d_i}{n}

s_d =\frac{\sum_{i=1}^n (d_i -\bar d)^2}{n-1}

\bar d=-0.7 represent the sample mean for the difference

\mu_d population mean (variable of interest)

s_d=1.32 represent the sample standard deviation

n=8 represent the sample size  

Confidence interval

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

\bar d \pm t_{\alpha/2} *\frac{s_d}{\sqrt{n}}  (1)

In order to calculate the critical value t we need to find first the degrees of freedom, given by:

df=n-1=8-1=7

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 table to find the critical value. The excel command would be: "=-T.INV(0.025,8)".And we see that t_(\alpha/2)=2.306

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

-0.7-2.306\frac{1.32}{\sqrt{8}}=-1.776    

-0.7+2.306\frac{1.32}{\sqrt{8}}=0.376    

So on this case the 95% confidence interval for the difference would be given by (-1.776;0.376)

We are 95% confidence that the true mean difference is between -1.776 \leq \mu_d \leq 0.376. Since the confidence interval contains the value 0, we don't have enough evidence to conclude that hypnotism appear to be effective in reducing pain.

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Answer: d)
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