statistics
posted by Gee .
Pre study scores versus poststudy scores for a class of 120 college freshman english students were considerated. The residual plot for the least squares regression line showed no pattern. The least square regression line was y = 0.2 + 0.9x with a correlation coefficient r = 0.76. What percent of the variation of post study scores can be explained by the variation in prestudy scores? Based on the value of coefficient of determinartiton,we have ? Since the residual plot has no pattern we should? Suppose that one student had a prestudy score of 20 and a residual of 2.2?

Can someone please answer my question please