The coefficient of determination can be found using the following formula:
![r^2=\mleft(\frac{n(\sum ^{}_{}xy)-(\sum ^{}_{}x)(\sum ^{}_{}y)}{\sqrt[]{(n\sum ^{}_{}x^2-(\sum ^{}_{}x)^2)(n\sum ^{}_{}y^2-(\sum ^{}_{}y)^2}^{}}\mright)^2](https://tex.z-dn.net/?f=r%5E2%3D%5Cmleft%28%5Cfrac%7Bn%28%5Csum%20%5E%7B%7D_%7B%7Dxy%29-%28%5Csum%20%5E%7B%7D_%7B%7Dx%29%28%5Csum%20%5E%7B%7D_%7B%7Dy%29%7D%7B%5Csqrt%5B%5D%7B%28n%5Csum%20%5E%7B%7D_%7B%7Dx%5E2-%28%5Csum%20%5E%7B%7D_%7B%7Dx%29%5E2%29%28n%5Csum%20%5E%7B%7D_%7B%7Dy%5E2-%28%5Csum%20%5E%7B%7D_%7B%7Dy%29%5E2%7D%5E%7B%7D%7D%5Cmright%29%5E2)
Using a Statistics calculator or an online tool to work with the data we were given, we get
So the best aproximation of r² is 0.861
No. It is not. Only what's inside counts.
Answer:
This can be solved by using the empirical rule for a normal distribution.
Step-by-step explanation:
A. The number of skateboards given is one standard deviation above the mean. Approximately 68% of the data points lie within the range plus and minus one standard deviation of the mean. Therefore the required percentage is:
68 + 16 = 84%.
B. The given number of skateboards is two standard deviations above the mean. Approximately 95% of the data points lie within the range plus and minus two standard deviations of the mean. Therefore the required percentage is:
5/2 = 2.5%
C.The given number of skateboards is one standard deviations below the mean. Therefore the required percentage is:
16%.
