y ) . The term regression was introduced by (a) R.A. Fisher (b) Sir Francis Galton (c) Karl Pearson (d) Croxton and Cowden . If r =– , then correlation between the variables (a) perfect positive (b) perfect negative (c) negative (d) no correlation .
The coefficient of correlation describes (a) the magnitude and direction (b) only magnitude (c) only direction (d) no magnitude and no direction . If Cov( x , y )=– . , σ x = . , σ y = .
Find correlation coefficient. (a) – . (b) . (c) – (d – .
Miscellaneous Problems . Find the coefficient of correlation for the following data: Y . Calculate the coefficient of correlation from the following data: ∑ X = , ∑ Y =– , ∑ X = , ∑Y = , ∑ XY =– , N = . Calculate the correlation coefficient from the data given below: Y - - .
Calculate the correlation coefficient from the following data: ∑ X = , ∑Y= , ∑X = , ∑ Y = , ∑ XY = , N = . A random sample of recent repair jobs was selected and estimated cost , actual cost were recorded. Estimated cost Actual cost Calculate the value of spearman’s correlation. .
The following data pertains to the marks in subjects A and B in a certain examination. Mean marks in A = . , Mean marks in B = . standard deviation of marks in A = .
and Standard deviation of marks in B = . . coefficient of correlation between marks in A and marks in B is . .
Give the estimate of marks in B for candidate who secured marks in A. . X and Y are a pair of correlated variables. Ten observations of their values ( X , Y ) have the following results.
∑ X = , ∑ XY = , ∑ X = , ∑ Y = , Predict the value of y