The Slope of a Fitted Line

Today’s
Goal

❏ I can use the slope of

a line fit to data in a
scatter plot to say
how the variables are
connected in
real-world situations.

Estimating Slope

Activate: Warm Up
Activity 6.1
● Think Pair Share

Estimate the
slope of the line.

Begin working on
your own. (1 min)

It’s better to use
points that are far
apart rather than
close together when
estimating slope!

Interpreting Slopes

Comprehend/Apply: Activity 6.3
● MLR8: Discussion Supports

An equation for the line is y = -0.073x + 17,404.485.
What is the slope? What does that slope tell us?

​m = -0.073

For every increase of 1 mile, the price of the car decreases by $0.073.

y = 5,520.619x – 1,091.393

● What is the meaning of the slope?

​If the weight of the diamond increases by one carat, the price increases by $5, 521.

y = -0.011x + 40.604

● What is the meaning of the slope?

​If the car increases by 1 kg, the fuel efficiency decreases by 0.011 mpg.

The model for energy
consumption and
temperature predicted a
0.59 kilowatt hour increase
in energy consumption
every 1 degree increase in
temperature.

y = 0.59x – 21.912

​Estimate how much the temperature would need to increase to raise energy consumption by 6 kilowatt hours. Substitute x = 6.

What was the easiest way
to find the slope for each
situation?

What is the difference between a
positive and negative slope in
your interpretations?

Positive or Negative

Comprehend/Apply: Activity 6.4
● MLR1: Stronger and Clearer Each Time

linear
associations

A linear association is present
when the points in a scatter
plot suggest that a linear
model would fit the data well.

Still other data sets have
no association when the data
appears random and no curve
would represent the data well.

In this activity…

identify if the data has a
linear association or not.

If it does, what type of
slope would it have?

Which of these
scatter plots show
evidence of…

● a positive

association?

● a negative

association?

● no association?

What strategy did you
use to determine if
the data had a linear
association?

Would you be able to
notice a linear
association from the
data in a table?

Organize: Activity Synthesis

What does it mean to
have a positive
association?

How did you
determine if the data
had a positive
assoication?

What are other pairs
of things that you
conjecture would
have a negative,
linear association?

Let’s
synthesize
our learning!

How would you describe the trend in the
scatter plot?

As the height
of a dog
increases, its
weight tends
to increase!

Organize: Lesson Synthesis

The slope of a fitted line is 4.25. What
does that tell us about the dogs?

For every 1
inch increase
in dog height,
the predicted
weight is 4.25
pounds.

Today’s
Goals

❏ I can use the slope of a

line fit to data in a
scatter plot to say how
the variables are
connected in real-world
situations.

Trends in the Price
of Used Cars

Apply/Summarize
Cool Down Activity 6.5

6-6-5: Trends in the Price of Used Cars

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