What’s 7c(-31) answer

Some types of algae have the potential to cause damage to river ecosystems. Suppose the accompanying data on algae colony densit

Phantasy [73]

Answer:

$y=-2.95836 x +234.56159$

Step-by-step explanation:

We assume that th data is this one:

x: 50, 55, 50, 79, 44, 37, 70, 45, 49

y: 152, 48, 22, 35, 43, 171, 13, 185, 25

a) Compute the equation of the least-squares regression line. (Round your numerical values to five decimal places.)For this case we need to calculate the slope with the following formula:

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

Where:

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

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

So we can find the sums like this:

$\sum_{i=1}^n x_i =50+ 55+ 50+ 79+ 44+ 37+ 70+ 45+ 49=479$

$\sum_{i=1}^n y_i =152+ 48+ 22+ 35+ 43+ 171+ 13+ 185+ 25=694$

$\sum_{i=1}^n x^2_i =50^2 + 55^2 + 50^2 + 79^2 + 44^2 + 37^2 + 70^2 + 45^2 + 49^2=26897$

$\sum_{i=1}^n y^2_i =152^2 + 48^2 + 22^2 + 35^2 + 43^2 + 171^2 + 13^2 + 185^2 + 25^2=93226$

$\sum_{i=1}^n x_i y_i =50*152+ 55*48+ 50*22+ 79*35+ 44*43+ 37*171+ 70*13+ 45*185+ 49*25=32784$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=26897-\frac{479^2}{9}=1403.556$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}=32784-\frac{479*694}{9}=-4152.22$

And the slope would be:

$m=-\frac{-4152.222}{1403.556}=-2.95836$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{479}{9}=53.222$

$\bar y= \frac{\sum y_i}{n}=\frac{694}{9}=77.111$

And we can find the intercept using this:

$b=\bar y -m \bar x=77.1111111-(-2.95836*53.22222222)=234.56159$

So the line would be given by:

$y=-2.95836 x +234.56159$

7 0

3 years ago

over a season in a women's basketball league jackson scored 41 more points than the second highest scorer leslie. Together they

vlabodo [156]

First, you know that Jackson (let call her J) scored 41 more points than L (Leslie). What we don't know is how many points L scored so we can use a variable that will be 'x'.
So the equation will be J=41+x.
We also know that the total points is 1,189.
To find out what x is we first subtract 1,189-41. We then get 1,148.
We are now left with 2x and 1,148 so we divide 1,148 by 2 and get 574.
574=x so now we can plug that in.
J= 574+41
Jackson scored 615 points and Leslie scored 574 points

(You can use bar modeling to do solve this problem. An example of bar modeling is shown below.

3 0

3 years ago

HELP! LOTS OF POINTS

seropon [69]

Use the equation=
x^2+5^2=9^2
x^2+25=81
x^2+25-25=81-25
x^2=56
$\sqrt{x} = \sqrt{56}$
x=7.48331477355

5 0

3 years ago

Read 2 more answers

You know what to do?

Juliette [100K]

Answer:

^

Step-by-step explanation:

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6 0

2 years ago

Read 2 more answers

I would like to see the process to this question and the answer to it: <br> 2(cos 80+ i sin 80)

Bezzdna [24]

<span>(-0.220774488 - 1.98777731 i) So that should be your answer
And i put that into my calculator so i don't know how to get the steps i really sorry i wish i knew

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7 0

3 years ago