Aregression analysis can be used to determine a. if a linear relationship exists between two categorical variables. b. a cause-and-effect relationship between two variables. c. if the difference in the population means may be zero. d. if a linear relationship exists between two quantitative variables.

Option (d) is correct.

Step-by-step explanation:

Regression analysis can be used to determine if there is any linear relationship exists between the two quantitative variables.

There are one dependent variable and one or more than one independent variable in a single regression equation.

After running a simple regression, we get to know the relationship between the dependent variable and explanatory variable.

Various statistical software are used for running regression like STATA, E- Views, SPSS, etc.  

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.