What is the value of the expression 1/2x2/5 ÷2/6

Which of the following geometric objects could have it length measured

anastassius [24]

Answer:

You need to attach the image

Step-by-step explanation:

3 0

2 years ago

In selecting a sulfur concrete for roadway construction in regions that experience heavy frost, it is important that the chosen

Lesechka [4]

Step-by-step explanation:

Given - In selecting a sulfur concrete for roadway construction in regions that experience heavy frost, it is important that the chosen concrete has a low value of thermal conductivity in order to minimize subsequent damage due to changing temperatures. Suppose two types of concrete, a graded aggregate and a no-fines aggregate, are being considered for a certain road. The table below summarizes data on thermal conductivity from an experiment carried out to compare the two types of concrete.

Type ni xi si

Graded 42 0.486 0.187

No-fines 42 0.359 0.158

To find - a. Formulate the above in terms of a hypothesis testing problem.

b. Give the test statistic and its reference distribution (under the null hypothesis).

c. Report the p-value of the test statistic and use it to assess the evidence that this sample provides on the scientific question of difference in mean conductivity of the two materials at the 5% level of significance.

Proof -

a.)

Hypothesis testing problem :

H0 : There is significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.

H1 : There is no significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.

b)

Test statistic :

$Z = \frac{x_{1} - x_{2} }{\sqrt{\frac{s_{1} ^{2} }{n_{1}} + \frac{s_{2}^{2} }{n_{2}} } }$

$Z = \frac{0.486 - 0.359 }{\sqrt{\frac{0.03496 }{42} + \frac{0.02496 }{42} } }$

$Z = \frac{0.127 }{\sqrt{0.001468}}$

$Z = \frac{0.127 }{0.0377}$

⇒Z(cal) = 3.3687

Z(tab) = 1.96

As Z (cal) > Z(tab)

So, we reject H0 at 5% Level of significance

p-value = 0.99962

Hence

There is significant difference in mean conductivity at the two materials.

5 0

3 years ago

If x+y= 15, y+z=25, and x+z=20, what is the arithmetic mean of x,y, and z

Mama L [17]

X + y = 15
Rearrange this to isolate for x.
x = 15 - y

x + z = 20
Rearrange this to isolate for x also.
x = 20 - z

Since they are both equal to x, that means they are equal to each other (x = x)

Set them equal to each other.

15 - y = 20 - z
Now, isolate for y.

y = 15 - 20 + z

Now, use y + z = 25 and isolate for y.
y = 25 - z

Since they are both equal to y, we set them equal to each other.

15 - 20 + z = 25 - z
Solve for z
z + z = 25 - 15 + 20
2z = 30
2z/2 = 30/z
z = 15

Now you can plug the value for z into the other equations to find y and x.

x + z = 20
x +15 = 20
x = 20-15
x = 5

y + z = 25
y + 15 = 25
y = 25 - 15
y = 10

6 0

3 years ago

I rlly need help on this guys it’s due tomorrow!! The outside radius of a truck tire is 11 inches. Approximately how far will th

Sergeeva-Olga [200]

Answer:

207.24 inches

Hope this helps

Step-by-step explanation:

first you need to find the circumference...

2pi R (r=radius=11)

2 x 3.14 x 11 = 69.08 (i'm using 3.14 as pi so yea...)

3 rotations...