a regression analysis on a set of data (with two variables, X and Y) outcomes a value of r-square = 78.5 What would be the interpretation of this value?

Advertising aimed at teenagers tends to contain dance-beat music, adventure, and a fast pace rather than words. To test to see how teenagers respond to different types of commercials, 150 teenagers then watched a set of commercials with dance-beat music, adventure, and a fast pace. After the commercials, the teenagers were asked whether they would want to buy the product and 102 responded that they would buy the product. Another sample of 125 teenagers where shown a set of commercialscomprised primarily of words. After the commercials, the teenagers were asked whether they would buy the product and 60 responded that they would like to buy the product. Based on both samples, at the 5% level of significance, test the hypothesis that there is at least a 10% difference in the proportion of teenagers who would buy the product after watching the different types of commercials?

Interpret the regression coefficient of X3 in relation to the Y ( X3 unit is mile)  Y =  58.286 + 13.7604 * X3

Using your favorite statistics software package, you generate a scatter plot with a regression equation and correlation coefficient. The regression equation is reported as y=−24.94x+53.67 and the r=−0.78What percentage of the variation in y can be explained by the variation in the values of x?r² = ______% (Report exact answer, and do not enter the % sign)