The regression lines are identical if r is equal to
The two lines of regression coincide i.e. become identical when r = –1 or 1 or in other words, there is a perfect negative or positive correlation between the two variables under discussion.
The regression lines are perpendicular to each other if r is equal to
Feature of Least Square regression lines are——— The sum of the deviations at the Y’s or the X’s from their regression lines are zero.
The coefficient of determination is defined by the formula
The line Y = 13 –3X /2 is the regression equation of
In the line Y = 19 – 5X/2 , byx is equal to
The line X = 31/6 — Y/6 is the regression equation of
In the equation X = 35/8 – 2Y/5, bxy is equal to
The square of coefficient of correlation ‘r’ is called the coefficient of
A relationship r2 = 1 — 580 is not possible 300
Whatever may be the value of r, positive or negative, its square will be
Simple correlation is called
A scatter diagram indicates the type of correlation between two variables.
If the pattern of points ( or dots) on the scatter diagram shows a linear path diagonally across the graph paper from the bottom left- hand corner to the top right, correlation will be
The correlation coefficient being +1 if the slope of the straight line in a scatter diagram is
The correlation coefficient being –1 if the slope of the straight line in a scatter diagram is
The more scattered the points are around a straight line in a scattered diagram the _______ is the correlation coefficient.
If the values of y are not affected by changes in the values of x, the variables are said to be
If the amount of change in one variable tends to bear a constant ratio to the amount of change in the other variable, then correlation is said to be
Variance may be positive, negative or zero.
Covariance may be positive, negative or zero.
Correlation coefficient between x and y = correlation coefficient between u and v
In case ‘ The ages of husbands and wives’ ———— correlation is
In case ‘Shoe size and intelligence’
In case ‘Insurance companies’ profits and the no of claims they have to pay “——
In case ‘Years of education and income’———
In case ‘Amount of rainfall and yield of crop’——
For calculation of correlation coefficient, a change of origin is
The relation rxy = cov (x,y)/sigma x* sigma y is
A small value of r indicates only a _________ linear type of relationship between the variables.
Two regression lines coincide when
Neither y nor x can be estimated by a linear function of the other variable when r is equal to
When r = 0 then cov (x,y) is equal to
When the variables are not independent, the correlation coefficient may be zero
bxy is called regression coefficient of
This we denote by a new notation bxy. Here, the first script x indicates that it is a dependent variable and the second y variable denotes to independent variable. And, this bxy is called the regression coefficient of x on y.
byx is called regression coefficient of
The slopes of the regression line of y on x is
The slopes of the regression line of x on y is
The angle between the regression lines depends on
If x and y satisfy the relationship y = –5 + 7x, the value of r is