. In television's early years, most commercials were 60 seconds long. Now, however, com- mercials can be any length. The objective of commercials remains the same-to have as many viewers as possible remember the product in a favorable way and eventually buy it. In an experiment to determine how the length of a commercial aects people's memory of it, 60 randomly selected people were asked to watch a 1 hour television program. In the middle of the show, a commercial advertising a brand of toothpaste appeared. Some viewers watched a commercial that lasted for 20 seconds, others watched one that lasted for 24 seconds, 28 seconds,..., 60 seconds. The essential content of the commercials was the same. After the show, each person was given a test to measure how much he or she remembered about the product. The commercial times and test scores are stored here Lenght 52 40 36 28 44 16 48 52 60 44 36 44 60 24 32 52 36 Test 24 20 16 11 10 4 24 18 16 15 14 15 24 10 1 8 9 a) Create the regression line. b) Determine the standard error of estimate and describe what this statistic tells you about the regression model. c) Determine the coecient of determination. What does this statistic tell you about how well the linear regression model ts?