Liner Models applications: slope, y-intercept, domain, range.

1. More about the stuff
outs
e and i de t
lin h e lin
t he e
on
Between the Painted Lines by flickr user Caveman 92223

2. In testing the effectiveness of a new antibacterial spray, a biochemist
recorded the number of bacteria present in a tissue culture after the spray
had been present for different periods of time. The data are recorded in
the table below:
HOMEWORK
a) Find the slope.
(Use a regression equation.)
What does it mean?
b) Find the y-intercept.
What does it represent? c) Write the equation of the line.

3. In testing the effectiveness of a new antibacterial spray, a biochemist
recorded the number of bacteria present in a tissue culture after the spray
had been present for different periods of time. The data are recorded in
the table below:
HOMEWORK
RANGE
d) After how many hours
would 25 bacteria be present?
e) State the largest value and
the smallest value of the domain. Domain
f) State the largest value and
the smallest value of the range.

4. The following data shows the age of certain cars and their
corresponding prices:
HOMEWORK
Graph age vs.price.
Construct a scatter plot of the data.
Determine the line of best fit.
1. What is the equation of the line?
2. What is the value of the y-intercept? What is its real-world
significance?
3. What is the real-world significance of the slope?
4. Is this a good model for car prices? Why or why not?

5. In an experiment, the following masses were attached to
a spring. As they were attached, the following elongations
were recorded:
HOMEWORK
1. What is the independent variable?
2. Use your graphing calculator to
plot the elongation against mass.
3. Use your calculator to find a regression line (line
of best fit) for the data. What is the y-intercept?
4. Select two points in the table and use
them to calculate the slope of the line.
5. Is it the same in the equation of the line?
6. Do you think that this model for the elongation of the
spring is always accurate? What do you think would
happen if the mass were increases to 15 kg?