Answer:
A. R2 = 0.6724, meaning 67.24% of the total variation in test scores can be explained by the least‑squares regression line.
Step-by-step explanation:
John is predicting test scores of students on the basis of their home work averages and he get the following regression equation
y=0.2 x +82.
Here, dependent variable y is the test scores and independent variable x is home averages because test scores are predicted on the basis of home work averages.
The coefficient of determination R² indicates the explained variability of dependent variable due to its linear relationship with independent variable.
We are given that correlation coefficient r= 0.82.
coefficient of determination R²=0.82²=0.6724 or 67.24%.
Thus, we can say that 67.24% of total variability in test scores is explained by its linear relationship with homework averages.
Also, we can say that, R2 = 0.6724, meaning 67.24% of the total variation in test scores can be explained by the least‑squares regression line.
<span><span>uno. 1y = 6 - x/2.
</span><span> dos. 2x = 6 - y/2.
</span><span>tres. 3x = 6 - y/2. y/2 = 6 - x. y = 12 - 2x.
</span><span>
quatro. 4<span>f-1(x) = 12 - 2x.</span></span></span>
X = -4, nothing else, its just vertical
The two numbers are 41 & 37.
The way to solve this is by setting up an equation. We know that 2 numbers are going to equal 78, so here would be the general equation (let x represent the number we don't know):
(x) + (x + 4) = 78
Now, we need to simplify it (combine like terms):
2x + 4 = 78
Then you can solve it like any other equation. Subtract 4 on both sides:
2x = 74
Divide by 2 on both sides:
x = 37.
So, now you know one number is equal to 37 and that the other is 37 + 4.
That's how you get 37 & 41.