MATH 221 Week 7 Quiz 2

MATH 221 Week 7 Quiz 2 | Devry University

Week 7: Quiz

Question 1

 (CO 6) The coefficient of determination is represented by what notation?  

·         r2  

·         r  

·         ρ 

·         β

 

 Question 2

 (CO 6) Two variables have a positive linear correlation. Does the independent variable increase or decrease as the dependent variable increases?  

·         Independent variable increases  

·         Independent variable would remain the same  

·         Cannot determine from information given  

·         Independent variable decreases

 

 Question 3

 (CO 6) Find the regression equation for the following data set

x          245       187       198       189       176       266       210       255

y          50         54        55        78        44        41        51        60  

·         ŷ = -0.09x + 74.17  

·         cannot be determined  

·         ŷ = 74.17x – 0.09  

·         ŷ = 0.09x – 74.17

 

 Question 4

 (CO 6) A student wants to determine if a higher quality diet will improve their grade point average. Which variable would be the explanatory variable?  

·         The student    

·         The higher quality diet 

·         Their GPA

·         The number of classes taken

 

Question 5

 (CO 6) A value of the independent variable that corresponds to the value of yi would be given the notation of:  

·         m  

·         b  

·         x1  

·         xi

 

Question 6

 (CO 6) The graph for a linear regression crosses the y axis in positive value. Where would the y-intercept of the regression line be located on the y-axis?  

·         To the right of 0  

·         To the left of 0  

·         Below 0  

·         Above 0

 

 Question 7

 (CO 6) What would be the notation for an estimate of y for a specific value of x?  

·         yi  

·         ŷ  

·         ȳ  

·         b

 

 Question 8

 (CO 6) Find the regression equation for the following data set

x          9          1          5          2          4          13         19

y          1          2          8          3          7          9          12  

·         ŷ = 0.44x + 2.68   

·         ŷ = 2.68x - 0.44  

·         ŷ = -0.44x + 2.68  

·         ŷ = -2.68x + 0.44

 

 

Question 9

 (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=44.  

·         260.4    

·         92.9  

·         Meaningless result  

·         90.6

 

 Question 10

 (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=297.  

·         Meaningless result  

·         -8.02  

·         27.62  

·         6.92

 

 Question 11

 (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=39.  

·         174.2  

·         97.0   

·         -169.0  

·         Meaningless result

 

 Question 12

 (CO 6) If the linear correlation coefficient is 0.644, what is the value of the coefficient of determination?  

·         -0.415  

·         -0.802  

·         0.415

·         0.802

 

 

Question 13

 (CO 6) If the linear correlation coefficient is -0.491, what is the value of the coefficient of determination?  

·         -0.241  

·         -0.982  

·         0.982  

·         0.241

 

 Question 14

 (CO 6) If the coefficient of determination is 0.521, what percentage of the variation in the data about the regression line is explained?  

·         50.0%  

·         47.9%    

·         52.1%  

·         48.8%

 

 Question 15

 (CO 6) If the coefficient of determination is 0.618, what percentage of the variation in the data about the regression line is unexplained?  

·         38.2%  

·         30.2%  

·         68.1%  

·         61.8%

 

 Question 16

 (CO 6) If the explanatory variables explained more than 20% of the variation in the response variables, which of the following would be true? 

·         The coefficient of determination is above 0.2  

·         There are two response variables  

·         There are two explanatory variables  

·         The coefficient of determination is below 0.2

 

Question 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 41.8 inches tall and whose mother is 49.2 inches tall.  

·         44.34 inches  

·         56.44 inches  

·         46.56 inches  

·         44.95 inches

 

 Question 18

 (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.  

·         26.26 days  

·         25.82 days  

·         74.43 days  

·         18.93 days