D.
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Answer:

Step-by-step explanation:
Data of newly constructed decks treated with very clear deck sealants:
n₁ = 38,
, S₁ = 3.1
Data of newly constructed decks treated with sure seal deck sealants:
n₁ = 37,
, S₂ = 3.8
First calculate the degree of freedom
![df = \frac{[\frac{s_{1} ^{2} }{n_{1} } + \frac{s_{2} ^{2} }{n_{2} } ]^{2} }{\frac{(\frac{s_{1} ^{2} }{n_{1} } )^{2}}{n_{1}-1 } + \frac{(\frac{s_{2} ^{2} }{n_{2} } )^{2}}{n_{2}-1 }}](https://tex.z-dn.net/?f=df%20%3D%20%5Cfrac%7B%5B%5Cfrac%7Bs_%7B1%7D%20%5E%7B2%7D%20%7D%7Bn_%7B1%7D%20%7D%20%20%2B%20%5Cfrac%7Bs_%7B2%7D%20%5E%7B2%7D%20%7D%7Bn_%7B2%7D%20%7D%20%5D%5E%7B2%7D%20%7D%7B%5Cfrac%7B%28%5Cfrac%7Bs_%7B1%7D%20%5E%7B2%7D%20%7D%7Bn_%7B1%7D%20%7D%20%29%5E%7B2%7D%7D%7Bn_%7B1%7D-1%20%7D%20%2B%20%5Cfrac%7B%28%5Cfrac%7Bs_%7B2%7D%20%5E%7B2%7D%20%7D%7Bn_%7B2%7D%20%7D%20%29%5E%7B2%7D%7D%7Bn_%7B2%7D-1%20%7D%7D)
![df = \frac{[\frac{3.1^{2} }{38} + \frac{3.8^{2} }{37}]^2}{\frac{(\frac{3.1^{2} }{38})^{2} }{37} + \frac{(\frac{3.8^{2} }{37})^{2} }{36}}](https://tex.z-dn.net/?f=df%20%3D%20%5Cfrac%7B%5B%5Cfrac%7B3.1%5E%7B2%7D%20%7D%7B38%7D%20%2B%20%5Cfrac%7B3.8%5E%7B2%7D%20%7D%7B37%7D%5D%5E2%7D%7B%5Cfrac%7B%28%5Cfrac%7B3.1%5E%7B2%7D%20%7D%7B38%7D%29%5E%7B2%7D%20%7D%7B37%7D%20%2B%20%5Cfrac%7B%28%5Cfrac%7B3.8%5E%7B2%7D%20%7D%7B37%7D%29%5E%7B2%7D%20%7D%7B36%7D%7D)
df = 69.4
df = 70, α = 1 - 0.9 = 0.1



The wall pushes back with an equal and opposite force. So it pushes with a force of 36N in the opposite direction of the push. This allows you to move away from the wall.
Answer:
Alright, for question 7, the angle pair relationship is that they are corresponding angles.
So, 17x - 34 = 13x - 14. This means that 4x = 20, and x = 5 :)
For question 8, the angles are a linear pair. They are supplementary (adding to 180) :)
So, 37x - 17 + 33x - 13 = 180
This means taht 4x = 210, and x = 52.5? (I'm not sure if I screwed up on the arithmetic on this one, please correct if you find any mistakes!)