Elementary Statistics Learning Curve 5 Exam Graded A+

For a group of high school students, the correlation between math SAT score and total SAT score is about r = 0.9935 and r2 = 0.987. Which of the following is the correct interpretation of r2? - ANSWER-Math SAT scores explain about 98.7% of the variation in the total SAT scores. Since r2 is = (0.9935)2 = 0.9870, we interpret r2 as 98.7% of the variation in the y variable is explained by the x variable. In context, math SAT score explains about 98.7% of the variation in total SAT score. ______ ______ regression makes the sum of the squared prediction errors as small as possible. - ANSWER-Least Squares What type of study can be used to establish clearly that an explanatory variable causes changes in a response variable? A(n) ___________. - ANSWER-Experiment Dan has been saving money each week in a box under his bed. The equation that predicts how much money he has is ŷ = 20 + 4x, where x is the number of weeks he has added to his box. This equation tells us that he started with $____. - ANSWER-20 Which of the following regression estimates does not measure direction? A) R^2 B) Correlation Coefficient C) Slope - ANSWER-r^2 The term ____________ correlation refers to correlations based on averaged data. - ANSWER-Ecological The general form for a linear equation is given as: y = a + bx. a represents the y______. - ANSWER-Intercept True or False: A regression model (given in general form) as y = a + bx may be used if a curved or straight line describes the relationship between the variables x and y. - ANSWER-False True or False: Since the correlation is computed from the z-scores of the x and y variables and z-scores have no unit of measure, correlation is not affected by outliers. - ANSWER-False Residuals in regression represent ______ in the model. - ANSWER-Errors