1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
KiRa [710]
3 years ago
13

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

y (y) and rock surface area (x) for nine rivers is a subset of data that appeared in a scatterplot in a research paper in a scientific journal. x 50 55 50 79 44 37 70 45 49 y 152 53 22 35 38 166 13 185 25 (a) Compute the equation of the least-squares regression line. (Round your numerical values to five decimal places.)
Mathematics
1 answer:
Alex Ar [27]3 years ago
8 0

Answer:

y=-2.86 x +228.84

Step-by-step explanation:

We assume that the data is this one:

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

y: 152, 53, 22, 35, 38, 166, 13, 185, 25

Find the least-squares line appropriate for this data.  

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 + 53 + 22 + 35 + 38 + 166 + 13 + 185 + 25=689

\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 + 53^2 + 22^2 + 35^2 + 38^2 + 166^2 + 13^2 + 185^2 + 25^2=91641

\sum_{i=1}^n x_i y_i =50*152+ 55*53+ 50*22+ 79*35+ 44*38+ 37*166 +70*13+ 45*185+ 49*25=32654

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}=1403.56

S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}=32654-\frac{479*689}{9}=-4016.11

And the slope would be:

m=-\frac{4016.11}{1403.56}=-2.86

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

\bar x= \frac{\sum x_i}{n}=\frac{479}{9}=53.22

\bar y= \frac{\sum y_i}{n}=\frac{689}{9}=76.56

And we can find the intercept using this:

b=\bar y -m \bar x=76.56-(-2.86*53.22)=228.84

So the line would be given by:

y=-2.86 x +228.84

You might be interested in
What is the x-intercept for the following linear equation:
Alexandra [31]
The "x-intercept" occurs when y=0, because it is at this point that the equation touches the x axis.  So if you plug in y=0 into the equation you can solve for the x coordinate.

4x-2(0)-8=0

4x-8=0

4x=8

x=2

So the x-intercept is the point (2,0)
3 0
3 years ago
Given that (-3 3) is on the graph of f(x) find the corresponding point for the function f(x+1)
vredina [299]

Answer:

(-3, 4).

Step-by-step explanation:

When f(x) becomes f(x + 1), all that is happening is that the y-value increases by 1.

So, (-3, 3) becomes (-3, 3 + 1). That is (-3, 4).

Hope this helps!

3 0
3 years ago
Read 2 more answers
A florist has an order to make flower bouquets. The order calls for the use of 45 roses and 63 carnations. Each bouquet made wil
Solnce55 [7]
Highest common factor of 63 and 45 is 9.
Therefore there can be 9 bouquets each with 5 roses and 7 carnations
6 0
3 years ago
Read 2 more answers
Plz fill this out. in trying to pass. will give best answer​
yaroslaw [1]

Answer:

AB/ZX and CB/YX and AC/ZY

Step-by-step explanation:

Hope this helps :)

6 0
2 years ago
What is 7÷10 in faction form and improper fraction form ​
leonid [27]

Answer:

a) 7/10

b) There is no improper fraction form for this

5 0
3 years ago
Other questions:
  • The geometric sequence shown can be represented by the function y = 5n, where the domain of the function is
    7·1 answer
  • Tirzah wants to put a fence around her garden. She has 22 yards Of fence material. Does she have enough to go all the way around
    13·1 answer
  • Round each number to the nearest tenth.
    11·2 answers
  • The height, h, in feet of a gold ball above the ground after being hit into the air is given by the equation. H=-16t2+64t, where
    12·1 answer
  • A water tank is in the shape of a cone.Its diameter is 50 meter and slant edge is also 50 meter.How much water it can store In i
    10·1 answer
  • 12-w=1 solve for w help me please
    15·1 answer
  • If a car dealership buy as car for $9000, and wants to make a 45% profit, how much do they need to sell the car for? ​
    11·1 answer
  • I need held asp pls help me
    8·1 answer
  • find the volume of A trapezoid prism of height 4Km.The parallel sides of the base have length 8km and 5km. The other sides of th
    12·1 answer
  • While Anne was visiting her sister in Hillsdale, she bought a coat that was marked down 60% from an original price of $100. If t
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!