Mathematics - Probability and Statistics - Advanced - Regression analysis - Regression Problems

8 problems: (1) Given Σ(x-x̄)(y-ȳ)=120, Σ(x-x̄)²=40, find slope b. (2) Given b=3, x̄=5, ȳ=20, find intercept a. (3) 'r=0.85. Interpret this value.' (4) 'r²=0.72. What does this mean?' (5) 'Predict y when x=7 given ŷ=2.5x+10.' (6) 'Is it valid to use this model to predict y when x=50 if data ranges f