Answer:
A. 0.75
Step-by-step explanation:
The formula for the <em>correlation coefficient</em> r is
![r =\frac {n \sum{xy} - \sum{x}\sum{y}}{\sqrt{[n \sum{x^{2}}- (\sum{x})^{2}}][n \sum{y^{2}}- (\sum{y})^{2}]}](https://tex.z-dn.net/?f=r%20%3D%5Cfrac%20%7Bn%20%5Csum%7Bxy%7D%20-%20%5Csum%7Bx%7D%5Csum%7By%7D%7D%7B%5Csqrt%7B%5Bn%20%5Csum%7Bx%5E%7B2%7D%7D-%20%28%5Csum%7Bx%7D%29%5E%7B2%7D%7D%5D%5Bn%20%5Csum%7By%5E%7B2%7D%7D-%20%28%5Csum%7By%7D%29%5E%7B2%7D%5D%7D)
It's easier to use a statistical calculator, but this question probably expects you to do it by hand.
Let’s write a table for easy calculation.
<u> x y xy x² y² </u>
15 36 540 225 1296
13 22 286 169 484
12 6 72 144 36
<u>11 20 220 121 400
</u>
51 84 1118 659 2216
(Σx)² = 2601
(Σy)² = 7056
![r =\frac{4\times1118-51\times84}{\sqrt{[4\times659-2601][4\times2216-7056]}}](https://tex.z-dn.net/?f=r%20%3D%5Cfrac%7B4%5Ctimes1118-51%5Ctimes84%7D%7B%5Csqrt%7B%5B4%5Ctimes659-2601%5D%5B4%5Ctimes2216-7056%5D%7D%7D)
![r =\frac{4472-4284}{\sqrt{[2636-2601][8864-7056]}}](https://tex.z-dn.net/?f=r%20%3D%5Cfrac%7B4472-4284%7D%7B%5Csqrt%7B%5B2636-2601%5D%5B8864-7056%5D%7D%7D)



r = 0.747
The graph below shows that there is a poor correlation among the points.
Answer:
A is the correct set of coins
Answer:
20.97
Step-by-step explanation:
the total cost is the cost of the cologne plus the tax
total cost = 19.98+ .99
total cost = 20.97
SA=4pir^2
SA=4pi13^2
SA=4pi169
SA=676pi ft^2
Since the area of a triangle is 1/2 base times height it would be 50