What Is the Relationship Between Diamond Price and Carat Size

What is the relationship between diamond price and carat size? 307 diamonds were sampled and a straight-line relationship was hypothesized between y = diamond price (in dollars) and x = size of the diamond (in carats) . The simple linear regression for the analysis is shown below: Least Squares Linear Regression of PRICE $$\begin{array} { l c c c c c } \text { Predictor } & & & & \\\text { Variables } & \text { Coefficient } & \text { Std Error } & \text { T } & \text { P } & \\\text { Constant } & - 2298.36 & 158.531 & - 14.50 & 0.0000 & \\\text { Size } & 11598.9 & 230.111 & 50.41 & 0.0000 & \\& & & & & \\\text { R-Squared } & 0.8925 & \text { Resid. Mean Square (MSE) } & 1248950 \\\text { Adjusted R-Squared } & 0.8922 & { \text { Standard Deviation } } & 1117.56\end{array}$$ Interpret the coefficient of determination for the regression model.

A) We can explain 89.25% of the variation in the sampled diamond prices around their mean using the size of the diamond in a linear model.
B) There is sufficient evidence to indicate that the size of the diamond is a useful predictor of the price of a diamond when testing at alpha = 0.05.
C) We expect most of the sampled diamond prices to fall within $2235.12 of their least squares predicted values.
D) For every 1-carat increase in the size of a diamond, we estimate that the price of the diamond will increase by $1117.56.
11.6 Using the Model for Estimation and Prediction
1 Calculate and Compare Confidence Intervals for Mean of y