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3 years ago

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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3 years ago

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

plug in the 27 to any x...

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Hope this helped :)

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3 years ago

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iragen [17]

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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)

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3 years ago

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Effectus [21]

Earnings for 40 years without college are $30,000*40=$1,200,000
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Answer: d)

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3 years ago