CORRELATION AND REGRESSION -05-ASSIGNEMNT

1. For the bivariate frequency table for x and y x y 0 – 10 10 – 20 20 – 30 30 – 40 Sum 0 – 10 3 2 4 2 11 10 – 20 – 1 3 1 5 20 – 30 3 2 – – 5 30 – 40 – 6 7 – 13 Sum 6 11 14 3 34 Then the marginal frequency distribution for y is given by (a) 0 – 10 6 10 – 20 11 20 – 30 14 30 – 40 3 (b) 0 – 10 11 10 – 20 5 20 – 30 5 30 – 40 13 (c) 0 – 10 10 10 – 20 12 20 – 30 11 30 – 40 1 (d) None of these 2. The variables x and y represent height in cm and weight in gm respectively. The correlation between x and y has the unit (a) gm (b) cm (c) gm.cm (d) None of these 3. The value of is (a) (b) (c) (d) None of these 4. Karl Pearson’s coefficient of correlation is dependent (a) Only on the change of origin and not on the change of scale (b) Only on the change of scale and not on the change of origin (b) On both the change of origin and the change of scale (d) Neither on the change of scale nor on the change of origin 5. If X and Y are independent variable, then correlation coefficient is (a) 1 (b) – 1 (c) (d) 0 6. The value of the correlation coefficient between two variable lies between (a) 0 and 1 (b) – 1 and 1 (c) 0 and (d) – and 0 7. The coefficient of correlation between two variables x and y is given by (a) (b) (c) (d) 8. If r is the correlation coefficient between two variables, then (a) (b) (c) (d) 9. When the correlation between two variables is perfect, then the value of coefficient of correlation r is [Kurukshetra CEE 1993] (a) –1 (b) +1 (c) 0 (d) 10. If correlation between x and y is r, then between y and x correlation will be (a) –r (b) (c) r (d) 1- r 11. If r is the coefficient of correlation and then (a) (b) (c) 1 (d) None of these 12. If coefficient of correlation between the variables x and y is zero, then (a) Variables x and y have no relation (b) y decreases as x increases (c) y increases as x increases (d) There may be a relation between x and y 13. When the origin is changed, then the coefficient of correlation (a) Becomes zero (b) Varies (c) Remains fixed (d) None of these 14. If then (a) Correlation is negative and curved (b) Correlation is linear and negative (c) Correlation is in third and fourth quadrant (d) None of these 15. In a scatter diagram, if plotted points form a straight line running from the lower left to the upper right corner, then there exists a (a) High degree of positive correlation (b) Perfect positive correlation (c) Perfect negative correlation (d) None of these 16. If the two variables x and y of a bivariate distribution have a perfect correlation, they may be connected by (a) (b) (c) (d) None of these 17. If x and y are related as then the nature of correlation between x and y is (a) Perfect positive (b) Perfect negative (c) No correlation (d) None of these 18. If , , then equals (a) (b) (c) (d) 19. For a bivariable distribution , if then equals (a) 5 (b) 6 (c) 22 (d) 28 20. For covariance the number of variate values in the two given distribution should be [MP PET 2003] [MP PET 2003] [MP PET 2003] (a) Unequal (b) Any number in one and any number in the other (c) Equal (d) None of these 21. If x and y are independent variables, then (a) (b) (c) (d) 22. If x : x 3 4 8 6 2 1 y : 5 3 9 6 9 2 then the coefficient of correlation will be approximately (a) 0.49 (b) 0. 40 (c) – 0. 49 (d) – 0. 40 23. The coefficient of correlation for the following data x 20 25 30 35 40 45 y 16 10 8 20 5 10 will be (a) 0. 32 (b) – 0.32 (c) 0. 35 (d) None of these 24. Coefficient of correlation from the following data x : 1 2 3 4 5 y : 2 5 7 8 10 will be (a) 0. 97 (b) – 0.97 (c) 0. 90 (d) None of these 25. Coefficient of correlation between x and y for the following data x : 15 16 17 17 18 20 10 y : 12 17 15 16 12 15 11 will be approximately (a) 0. 50 (b) 0. 53 (c) – 0. 50 (d) – 0. 53 26. Karl Pearson’s coefficient of correlation between x and y for the following data x : 3 4 8 9 6 2 1 y : 5 3 7 7 6 9 2 (a) 0. 480 (b) – 0. 480 (c) 0. 408 (d) – 0. 408 27. The coefficient of correlation for the following data x : 1 2 3 4 5 6 7 8 9 10 y : 3 10 5 1 2 9 4 8 7 6 will be (a) 0. 224 (b) 0. 240 (c) 0. 30 (d) None of these 28. Karl Pearson’s coefficient of correlation between the marks in English and Mathematics by ten students Marks in English 20 13 18 21 11 12 17 14 19 15 Marks in Maths 17 12 23 25 14 8 19 21 22 19 will be (a) 0. 75 (b) – 0. 75 (c) 0. 57 (d) None of these 29. Coefficient of correlation between x and y for the following data x – 4 –3 –2 –1 0 1 2 3 4 y 16 9 4 1 0 1 4 9 16 will be (a) 1 (b) –1 (c) 0 (d) None of these 30. If the variances of two variables x and y are respectively 9 and 16 and their covariance is 8, then their coefficient of correlation is (a) (b) (c) (d) 31. If the co-efficient of correlation between x and y is 0. 28, covariance between x and y is 7.6 and the variance of x is 9, then the S.D. of y series is (a) 9.8 (b) 10. 1 (c) 9.05 (d) 10. 05 32. If Cov(x, y) = 0, then equals (a) 0 (b) 1 (c) – 1 (d) 33. Karl Pearson’s coefficient of correlation between the heights (in inches) of teachers and students corresponding to the given data Height of teachers x : 66 67 68 69 70 Height of students y : 68 66 69 72 70 is (a) (b) (c) (d) 0 34. The coefficient of correlation between x and y is 0.6, then covariance is 16. Standard deviation of x is 4, then the standard deviation of y is (a) 5 (b) 10 (c) 20/3 (d) None of these 35. If , then is (a) 0.121 (b) 0.603 (c) 0.07 (d) 0.347 36. Given and then the coefficient of correlation is (a) (b) (c) (d) 37. Let be the coefficient of correlation between two variables x and y. If the variable x is multiplied by 3 and the variable y is increased by 2, then the correlation coefficient of the new set of variables is (a) (b) (c) (d) None of these 38. Coefficient of correlation between the two variates X and Y is X 1 2 3 4 5 Y 5 4 3 2 1 (a) 0 (b) –1 (c) 1 (d) None of these 39. The coefficient of correlation between two variables X and Y is 0.5, their covariance is 15 and then (a) 5 (b) 10 (c) 20 (d) 6 40. Karl Pearson’s coefficient of rank correlation between the ranks obtained by ten students in Mathematics and Chemistry in a class test as given below Rank in Mathematics : 1 2 3 4 5 6 7 8 9 10 Rank in Chemistry : 3 10 5 1 2 9 4 8 7 6 i (a) 0.224 (b) 0.204 (c) 0.240 (d) None of these 41. The sum of squares of differences in ranks of marks obtained in Physics and Chemistry by 10 students in a test is 150, then the co-efficient of rank-correlation is given by (a) 0.909 (b) 0.091 (c) 0.849 (d) None of these 42. If a, b, h, k are constants, while U and V are , then (a) Cov (X, Y) = Cov (U, V) (b) Cov (X, Y) = hk Cov (U, V) (c) Cov (X, Y) = ab Cov (U, V) (d) Cov (U, V) = hk Cov (X, Y) 43. Let X, Y be two variables with correlation coefficient (X, Y) and variables U, V be related to X, Y by the relation U = 2X, V = 3Y, then (U, V) is equal t (a) (X, Y) (b) 6(X, Y) (c) (d) 44. If X and Y are two uncorrelated variables and if , , then r(u, v) is equal to (a) (b) (c) (d) None of these 45. If and n = 10, then the coefficient of correlation is (a) 0.4 (b) 0.3 (c) 0.2 (d) 0.1 46. Let X and Y be two variables with the same variance and U and V be two variables such that U = X + Y, V = X – Y. Then Cov (U, V) is equal to (a) Cov (X, Y) (b) 0 (c) 1 (d) – 1 47. If there exists a linear statistical relationship between two variables x and y, then the regression coefficient of y on x is (a) (b) (c) (d) , where are standard deviations of x and y respectively. 48. If is a line of regression of y on x and that of x on y, then (a) (b) (c) (d) None of these 49. Least square lines of regression give best possible estimates, when (X, Y) is (a) <1 (b) > –1 (c) –1 or 1 (d) None of these 50. Which of the following statement is correct (a) Correlation coefficient is the arithmetic mean of the regression coefficient (b) Correlation coefficient is the geometric mean of the regression coefficient (c) Correlation coefficient is the harmonic mean of the regression coefficient (d) None of these 51. The relationship between the correlation coefficient r and the regression coefficients and is (a) (b) (c) (d) 52. If the coefficient of correlation is positive, then the regression coefficients (a) Both are positive (b) Both are negative (c) One is positive and another is negative (d) None of these 53. If and are both positive (where and are regression coefficients), then (a) (b) (c) (d) None of these 54. If and are regression coefficients and r is the coefficient of correlation, then (a) (b) (c) (d) None of these 55. If one regression coefficient be unity, then the other will be (a) Greater than unity (b) Greater than or equal to unity (c) Less than or equal to unity (d) None of these 56. If one regression coefficient be less than unity, then the other will be (a) Less than unity (b) Equal to unity (c) Greater than unity (d) All of the above 57. If regression coefficient of y on x is 2, then the regression coefficient of x on y is (a) 2 (b) (c) (d) None of these 58. The lines of regression of x on y estimates (a) x for a given value of y (b) y for a given value of x (c) x from y and y from x (d) None of these 59. The statistical method which helps us to estimate or predict the unknown value of one variable from the known value of the related variable is called (a) Correlation (b) Scatter diagram (c) Regression (d) Dispersion 60. The coefficient of correlation between two variables x and y is 0.8 while regression coefficient of y on x is 0.2. Then the regression coefficient of x on y is (a) –3.2 (b) 3.2 (c) 4 (d) 0.16 61. If the lines of regression coincide, then the value of correlation coefficient is (a) 0 (b) 1 (c) 0.5 (d) 0.33 62. Two lines of regression are and . Then correlation coefficient between x and y is (a) (b) (c) (d) 63. If the two lines of regression are and , then the means of x and y are (a) (b) (c) (d) 4, 7 64. The two regression lines for a bivariate data are and . If , then is (a) 50 (b) (c) – 50 (d) 65. The two regression lines are and . What is the correlation coefficient between x and y (a) (b) (c) (d) None of these 66. If the two regression coefficient between x and y are 0.8 and 0.2, then the coefficient of correlation between them is (a) 0.4 (b) 0.6 (c) 0.3 (d) 0.5 67. The two lines of regression are given by and . The coefficient of correlation between x and y is (a) (b) (c) (d) 68. If the lines of regression be and and , then the coefficient of correlation is (a) – 0.5 (b) 0.5 (c) 1.0 (d) – 1.0 69. A student obtained two regression lines as and . Then the regression line of y on x is (a) (b) (c) Neither of the two (d) 70. If and are regression coefficients of y on x and x on y respectively, then which of the following statement is true (a) (b) (c) (d) 71. Angle between two lines of regression is given by (a) (b) (c) (d) 72. If acute angle between the two regression lines is , then (a) (b) (c) (d) 73. If the angle between the two lines of regression is 90°, then it represents (a) Perfect correlation (b) Perfect negative correlation (c) No linear correlation (d) None of these 74. If and are the two regression lines respectively, then the correlation co-efficient between x and y is (a) + 1 (b) –1 (c) (d) 75. For a perfect correlation between the variables x and y, the line of regression is where ; then (a) 0 (b) –1 (c) 1 (d) None of these 76. If two random variables X and Y of a bivariate distribution are connected by the relationship , then correlation coefficient equals (a) 1 (b) –1 (c) 2/3 (d) –2/3 77. Two variables x and y are related by the linear equation . The coefficient of correlation between the two is +1, if (a) a is positive (b) b is positive (c) a and b both are positive (d) a and b are of opposite sign 78. If the two lines of regression are and , then the correlation coefficient between x and y is (a) +1 (b) –1 (c) (d) 79. The error of prediction of x from the required line of regression is given by, (where  is the co-efficient of correlation) (a) (b) (c) (d) 80. Probable error of r is (a) (b) (c) (d) 81. For the following data x y Mean 65 67 Standard deviation 5.0 2.5 Correlation coefficient 0.8 Then the equation of line of regression of y on x is (a) (b) (c) (d) 82. If the lines of regression of y on x and that of x on y are and respectively, then (a) (b) (c) (d) 83. From the following observations . The line of regression of y on x is (a) (b) (c) (d) None of these 84. If the variance of and regression equations are and , then the coefficient of correlation between x and y and the variance of y respectively are (a) 0.6; 16 (b) 0.16; 16 (c) 0.3; 4 (d) 0.6; 4 85. If the two lines of regression are and , then value of x for is (a) 4 (b) –9 (c) – 4 (d) None of these 86. Which of the following two sets of regression lines are the true representative of the information from the bivariate population I. and II. and (a) Both I and II (b) II only (c) I only (d) None of these 87. Out of the two lines of regression given by and , the regression line of x on y is (a) (b) (c) The given lines cannot be the regression lines (d) 88. Regression of savings (S) of a family on income Y may be expressed as , where a and m are constants. In a random sample of 100 families the variance of savings is one-quarter of the variance of incomes and the correlation coefficient is found to be 0.4. The value of m is (a) 2 (b) 5 (c) 8 (d) None of these