Scatterplots and Correlation
Describe the strength and direction of the scatterplot.
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weak positive
Find the regression equation for the data table.
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y = -1.414x + 9.952
r = -0.952
Use the elimination method to solve the following:
-4x-2y=-12
4x+8y=-24
(6, -6)
How many solution does this system of equations have?
x+y=4
and
x+y=9
no solution
Kristin spent $131 on shirts. Fancy shirts costs $28 and plain shirts cost $15. If she bought a total of 7 then how many of each kind did she buy?
x = # of fancy shirts, y = # of plain shirts
28x + 15y = 131
AND
x + y = 7
She bought 2 fancy shirts and 5 plain shirts.
Describe the strength and direction of the scatterplot.
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strong negative
Find the regression equation and r value for the data table.
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y = 0.026x + 4.452
r = 0.105
Use the elimination method to answer the following:
3x+y=9
4x-y=5
(2, 3)
How many solution does this system of equations have?
y=4x-3
and
2y=8x-6
infinite
There are 13 animals in the barn. Some are chickens and some are pigs. There are 40 legs in all. How many of each animal are there?
x = # of chickens, y = # of pigs
x + y = 13
AND
2x + 4y = 40
There are 6 chickens and 7 pigs.
Describe the scatterplot.
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No correlation.
The residual plot is _________ [random/non-random] so a linear model _____ [is/is not] a good fit for the data.
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The residual plot is non-random so a linear model is not a good fit for the data.
use the substitution method to solve the following:
-2x-3y=-13
y=-x+4
(-1, 5)
Choose the best method to solve.
4x-9y=13
and
y=x-2
substitution
A farmhouse shelters 10 animals. Some are pigs and some are ducks. Altogether there are 36 legs. How many of each animal are there?
x = # of pigs, y = # of ducks
x + y = 10
AND
4x + 2y = 36
There are 8 Pigs and 2 Ducks.
Correlation or Causation?
As the number of ice cream cones sold increases, the number of sunglasses sold increases.
correlation
The residual plot is _________ [random/non-random] so a linear model _____ [is/is not] a good fit for the data.
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The residual plot is random so a linear model is a good fit for the data.
use the substitution method to solve the following:
-4x+3y=1
y=4x-13
(5, 7)
Choose the best method to solve.
5x+8y=22
and
x+y=5
elimination
A class of 195 students went on a field trip. They took 7 vehicles, some cars and some buses. Find the number of cars and the number of buses the took if each car holds 5 students and each bus holds 45 students.
x = # of cars, y = # of buses
x + y = 7
AND
5x + 45y = 195
There are 4 Buses and 3 cars.
Correlation or Causation?
As the amount of time that snow if falling increases, the amount of snow on the ground increases.
causation
The residual plot is _________ [random/non-random] so a linear model _____ [is/is not] a good fit for the data.
Show image in flipchart.
The residual plot is non-random]so a linear model is not a good fit for the data.
Use the elimination methos to solve the following:
-10x+y=12
-2x-2y=-2
(-1, 2)
Choose the best method to solve.
x-y=4
and
y=x-2
substitution
A farmhouse shelters 11 animals. Some are goats and some are ducks. Altogether there are 34 legs. How many of each animal are there?
x = # of goats, y = # of ducks
x + y = 11
AND
4x + 2y = 34
There are 5 ducks and 6 goats.