The data records the average weight of the brain and body for a number of mammal species. There are 62 rows of data.
I have a task to take any two quantities that are related (min 10 data points is n=10)
Derive regression equation, calculate R square
Interpret your result
So to check if the two quantities are related I calculated chi-square which was 2648.193 which is higher than the critical value of 93.816 if we consider 0.005 significance level for a degree of freedom of 61.
Is this enough to say that these two quantities are related?
Also the equation of the trendline calculated using the below formula
where b=(sum(XY)-nX̅Y̅)/sum(X^2)-n(X̅^2) and a=Ybar-b*Xbar
y = 0.9665x + 91.004 and R² = 0.8727
Here I am not able to interpret the result of R². Does it means the equation takes into account about 87.27% of the reason out of total reasons responsible for variability of y?