MATH 221 Week 7 Quiz

1. Question: (CO 6) The coefficient of determination is represented by what notation? 2. Question: (CO 6) Two variables have a negative non-linear correlation. Does the independent variable increase or decrease as the dependent variable increases? 3. Question: (CO 6) Find the regression equation for the following data set 4. Question: (CO 6) An instructor wants to determine if a longer lesson would improve student test scores. Which variable would be the explanatory variable? 5. Question: (CO 6) A value of the slope of the regression line would be given the notation of: 6. Question: (CO 6) The graph for a linear regression crosses the y axis in negative values. Where would the y-intercept of the regression line be located on the y-axis? 7. Question: (CO 6) If there is a (-), or bar, above a variable, what does that indicate? 8. Question: (CO 6) Find the regression equation for the following data set 9. Question: (CO 6) A data set whose original x values ranged from 28 through 49 was used to generate a regression equation of ŷ = 2.9x – 34.7. Use the regression equation to predict the value of y when x=56. 10. Question: (CO 6) A data set whose original x values ranged from 241 through 290 was used to generate a regression equation of ŷ = -0.06x + 9.8. Use the regression equation to predict the value of y when x=240. 11. Question: (CO 6) A data set whose original x values ranged from 38 through 65 was used to general a regression equation of ŷ = -4.4x + 2.6. Use the regression equation to predict the value of y when x=55. 12. Question: (CO 6) If the linear correlation coefficient is 0.182, what is the value of the coefficient of determination? 13. Question: (CO 6) If the linear correlation coefficient is -0.677, what is the value of the coefficient of determination? 14. Question: (CO 6) If the coefficient of determination is 0.276, what percentage of the variation in the data about the regression line is explained? 15. Question: (CO 6) If the coefficient of determination is 0.798, what percentage of the variation in the data about the regression line is unexplained? 16. Question: (CO 6) A regression equation cannot have more than one. 17. (CO 6) The equation used to predict how tall a kitten will be as an adult is ŷ = 4.5 + 0.6x1 + 0.3x2, where x1 is the height of the sibling and x2 is the height of the mother. Use this equation to predict the height of a kitten whose sibling is 41.3 inches tall and whose mother is 44.9 inches tall. 18. Question: (CO 6) The equation used to predict how many days it takes a 15-year old to read the first Harry Potter book is ŷ = 1.5 + 2.82x1 – 1.04x2 days, where x1 is the weekly hours of other activities and x2 is the reading grade level. Use this equation to predict how many days it will take to read this book for someone with 12.8 weekly hours of other activities and a 10.9 reading grade level.