Solve simultaneously.
4x - y = 8
6x + y = 2
Multiply top equation by 6, and bottom equation by 4, to eliminate x, so that we can find y.
~
24x - 6y = 48
24x - 4y = 8
Subtract top from bottom to form one equation.
~
-2y = 40
Therefore y is 20.
Put y back in to an equation, such as 4x - y = 8.
~
4x - 20 = 8
4x = 28
x = 7
The assumptions of a regression model can be evaluated by plotting and analyzing the error terms.
Important assumptions in regression model analysis are
- There should be a linear and additive relationship between dependent (response) variable and independent (predictor) variable(s).
- There should be no correlation between the residual (error) terms. Absence of this phenomenon is known as auto correlation.
- The independent variables should not be correlated. Absence of this phenomenon is known as multi col-linearity.
- The error terms must have constant variance. This phenomenon is known as homoskedasticity. The presence of non-constant variance is referred to heteroskedasticity.
- The error terms must be normally distributed.
Hence we can conclude that the assumptions of a regression model can be evaluated by plotting and analyzing the error terms.
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Answer:

Step-by-step explanation:
<h3>METHOD 1:</h3>

<h3>METHOD 2:</h3>

Answer:
20% psyche test scores
Step-by-step explanation:
Given that every week, Bob plays the guitar for three hours, and his grade on each psych test is 75 percent.
Last week, after playing for three hours, Bob considered playing for an additional hour.
He decided to play for another hour and cut his study time by one hour, but last week his psych grade was 55 percent.
Bob's opportunity cost of the fourth hour of playing the guitar
=His cut in scores in psyche test
=20%
Answer:
a.) $3.20
b.) $102.40
$3,276.80
Step-by-step explanation:
0.2 times 2 five times is 3.2
0.2 times 2 ten times is 102.4
0.2 times 2 fifteen times is 3,276.8