If x and y are positively related, what is the coefficient of correlation when r2 = 23.4%? ________________.
If x and y are inversely related, what is the coefficient of correlation when r2 = 77.7%? ________________.
If x and y are positively related, what is the coefficient of correlation when r2 =...
If the correlation coefficient for X and Y is calculated to be - 95, what is the proportion of variance accounted for?
Prove that the regression R2 is identical to the square of the correlation coefficient between two variables Y and X. Regression functions are written in a form that suggests causation running from X to Y. Given your proof, does a high regression R2 present supportive evidence of a causal relationship? Can you think of some regression examples where the direction of causality is not clear? Is without a doubt
What is the correlation coefficient when the point (10.2) is excluded? r = _ (round to three decimal places as needed.) % 10.2.11 Question Help 104• Refer to the accompanying scatterplot. a. Examine the pattern of all 10 points and subjectively determine whether there appears to be a strong correlation between x and y. b. Find the value of the correlation coefficient r and determine whether there is a linear correlation. c. Remove the point with coordinates (1,10) and find...
What is a perfect correlation? Identify the correlation coefficient for a perfect correlation and describe what it means, in terms of your x and y variables.
4 a) Suppose Y X.Show in a diagram this function. What will be the correlation coefficient between X and Y? b)i) If the covariance between two variables is nogative, the correlation coefficient must be positive. True or False? ) If the covariance between two variables is zero. what does it suggest?
(a) Find the correlation coefficient ρX,Y . (b) Are X and Y independent? Explain why. Let (X, Y) have joint pdf given by 0 y 00, ey f(x, y) 0, o.w., (a) Find the correlation coefficient px,y. (20 pts) (b) Are X and Y independent? Explain why. (10 pts)
4.he sample correlation coefficient between X and Y, rxy Sx/Sx S where S-the covariance between X and Ys Σ(X-XM) (-Yu)/ n-1 Sx the standard deviation of X and Sy the standard deviation of Y I) If the covariance is positive, the correlation coefficient must be positive: True or False? ii) If the covariance is negative, the correlation coefficient must be positive: True or False? a) ii) The correlation coefficient must lie between 0 and 1. True or False? v)lf the...
If the correlation between variables x and y is r = .50, then the coefficient of determination is a. .50. b. 0. c. 1.00. d. .25.
4.2 The Correlation Coefficient 1. Let the random variables X and Y have the joint PMF of the form x + y , x= 1,2, y = 1,2,3. p(x,y) = 21 They satisfy 11 12 Mx = 16 of = 12 of = 212 2 My = 27 Find the covariance Cov(X,Y) and the correlation coefficient p. Are X and Y independent or dependent?
Discuss how the coefficient of determination and the coefficient of correlation are related and how they are used in regression analysis. What are some of the problems and drawbacks of the moving average forecasting model? What effect does the value of the smoothing constant have on the weight given to the past forecast and the past observed value?