Question

1.)

If the correlation between age of an auto and money spent for repairs is +.90

a) 81% of the variation in the money spent for repairs is explained by the age of the auto
b) 81% of money spent for repairs is unexplained by the age of the auto
c) 90% of the money spent for repairs is explained by the age of the auto
d) none of the above

2.) The correlation coefficient for X and Y is known to be zero. We then can conclude that:

a) X and Y have standard distributions
b) the variances of X and Y are equal
c) there exists no relationship between X and Y
d) there exists no linear relationship between X and Y
e) none of these

3.) What would you guess the value of the correlation coefficient to be for the pair of variables: "number of man-hours worked" and "number of units of work completed"?

a) Approximately 0.9
b) Approximately 0.4
c) Approximately 0.0
d) Approximately -0.4
e) Approximately -0.9

Answer 1

Answer

(1) coefficient of determination = r^2

= 0.9^2

= 0.81

= 81%

so, 81% of variation can be explained in dependent variable by the independent variable

option A

(2) correlation coefficient tells us whether there is any linear relationship between two variables or not. So, when the correlation coefficient is 0, then this means that there is no linear relationship

therefore, option D

(3) option A is correct because there is a strong positive correlation between the number of man hour worked and number of units of work completed as we know that if we do work, then the number of units of work completed will increase.

therefore, there is a strong positive correlation