7^12/7^4 is equal to a: 1^3 b: 3 c: 7^3 d: 7^8

A. R2 = 0.6724, meaning 67.24% of the total variation in test scores can be explained by the least‑squares regression line.

Step-by-step explanation:

John is predicting test scores of students on the basis of their home work averages and he get the following regression equation

y=0.2 x +82.

Here, dependent variable y is the test scores and independent variable x is home averages because test scores are predicted on the basis of home work averages.

The coefficient of determination R² indicates the explained variability of dependent variable due to its linear relationship with independent variable.

We are given that correlation coefficient r= 0.82.

coefficient of determination R²=0.82²=0.6724 or 67.24%.

Thus, we can say that 67.24% of total variability in test scores is explained by its linear relationship with homework averages.

Also, we can say that, R2 = 0.6724, meaning 67.24% of the total variation in test scores can be explained by the least‑squares regression line.