Rewrite y = 2x^2 – 8x + 4 in vertex form.<br> Please help!!

The least-squares regression model y =−3.4+5.2x and correlation coefficient r=−0.66 were calculated for a set of bivariate data

Makovka662 [10]

Answer:

$r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}$

For this case the value of r = -0.66

Now we can calculate the determination coeffcient:

$r^2 = (-0.66)^2 = 0.4356$

And then we can conclude that 43.56% of the variation in y can be explained by the explanatory variable

And then 100-43.56 = 56.44 % of the variation in y that cannot be explained by the explanatory variable

Step-by-step explanation:

For this case we need to calculate the slope with the following formula:

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

$\bar x= \frac{\sum x_i}{n}$

$\bar y= \frac{\sum y_i}{n}$

And we can find the intercept using this:

$b=\bar y -m \bar x$

And the model obtained for this case is:

$y = -3.4 +5.2 x$

The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.

And in order to calculate the correlation coefficient we can use this formula:

$r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}$

For this case the value of r = -0.66

Now we can calculate the determination coeffcient:

$r^2 = (-0.66)^2 = 0.4356$

And then we can conclude that 43.56% of the variation in y can be explained by the explanatory variable

And then 100-43.56 = 56.44 % of the variation in y that cannot be explained by the explanatory variable

8 0

3 years ago

3x - 1/5= x+1/3 Could you please solve this as soon as possible

VARVARA [1.3K]

x = 0.27

:)

good luck

4 0

3 years ago

3 ⅕ -⅔ divided by 2 ⅘

spin [16.1K]

Answer:

160/196

Step-by-step explanation:

it would be easier if you converted all fractions to improper fractions

so 3 1/5 would equal 16/5 and 2 4/5 would equal to 14/5

$\frac{14}{5} - \frac{2}{3}$ : to solve this you would need the same common denomenator,

to do this you can multiply 5 and 3 by something to make the lowest common denominator, which would be 15

thus

multiplying first fraction by 3 and the second by 5

42/15 - 10/15 = 32/15

now 32/15 divided by 14/5

the rule for dividing fractions, is flipping the fraction which you will be using to divide, and then multiplying it to the first fraction:

$\frac{32}{14}$ multiplied by $\frac{5}{14}$

thus, answer is 160/196

8 0

3 years ago

What is the term that contains the same variables raised to the same powers

stepan [7]

Answer: I think the term is “Like Terms”

6 0

3 years ago

Monica is counting books she has three stacks of some number of books and then 5 more books off to the side. Write a. Expression

AlladinOne [14]

Answer: n= number of books

n+5=?

Step-by-step explanation:

7 0

3 years ago

Rewrite y = 2x^2 – 8x + 4 in vertex form. Please help!!