Answer:
Correct statement: (a) and (b).
Step-by-step explanation:
R-squared is a statistical quantity that measures, just how near the values are to the fitted regression line. It is also known as the coefficient of determination.
The coefficient of determination is the squared value of the correlation coefficient.
That is,

The correlation coefficient between two variables is the measure of the strength and direction of the relationship between two variables.
Its values ranges from -1.00 to +1.00.
Although <em>r</em> can be negative but R² is always positive, since square of a negative number is also positive.
So the correct statements are:
a. cannot be negative
b. is the square root of the coefficient of correlation
Answer:
74.4 ,81.5 , median
Step-by-step explanation:
ed20 answers
Given:
Q = 0.0764 kJ = 764 J, heat input
W = -830 J, useful work done
From the 1st Law of Thermodynamics, the change in internal energy is
δE = Q - W
= 764 - (-830)
= 1594 J = 1.594 kJ
Answer: 1.59 kJ (two sig. fig.)