Gasoline consumption in the United States has been steadily increasing. Consumption data from 1994 to 2004 is shown in
[link] .
http://www.bts.gov/publications/national_transportation_statistics/2005/html/table_04_10.html Determine whether the trend is linear, and if so, find a model for the data. Use the model to predict the consumption in 2008.
Year
'94
'95
'96
'97
'98
'99
'00
'01
'02
'03
'04
Consumption (billions of gallons)
113
116
118
119
123
125
126
128
131
133
136
The scatter plot of the data, including the least squares regression line, is shown in
[link] .
We can introduce new input variable,
$\text{\hspace{0.17em}}t,$ representing years since 1994.
The least squares regression equation is:
$C(t)=113.318+2.209t$
Using technology, the correlation coefficient was calculated to be 0.9965, suggesting a very strong increasing linear trend.
Using this to predict consumption in 2008
$\text{\hspace{0.17em}}(t=14),$
Scatter plots show the relationship between two sets of data. See
[link] .
Scatter plots may represent linear or non-linear models.
The line of best fit may be estimated or calculated, using a calculator or statistical software. See
[link] .
Interpolation can be used to predict values inside the domain and range of the data, whereas extrapolation can be used to predict values outside the domain and range of the data. See
[link] .
The correlation coefficient,
$\text{\hspace{0.17em}}r,$ indicates the degree of linear relationship between data. See
[link] .
A regression line best fits the data. See
[link] .
The least squares regression line is found by minimizing the squares of the distances of points from a line passing through the data and may be used to make predictions regarding either of the variables. See
[link] .
Section exercises
Verbal
Describe what it means if there is a model breakdown when using a linear model.
When our model no longer applies, after some value in the domain, the model itself doesn’t hold.
A regression was run to determine whether there is a relationship between hours of TV watched per day
$\text{\hspace{0.17em}}(x)\text{\hspace{0.17em}}$ and number of sit-ups a person can do
$\text{\hspace{0.17em}}(y).\text{\hspace{0.17em}}$ The results of the regression are given below. Use this to predict the number of sit-ups a person who watches 11 hours of TV can do.
hi can you give another equation I'd like to solve it
Daniel
what is the value of x in 4x-2+3
Olaiya
if 4x-2+3 = 0
then
4x = 2-3
4x = -1
x = -(1÷4) is the answer.
Jacob
4x-2+3
4x=-3+2
4×=-1
4×/4=-1/4
LUTHO
then x=-1/4
LUTHO
4x-2+3
4x=-3+2
4x=-1
4x÷4=-1÷4
x=-1÷4
LUTHO
A research student is working with a culture of bacteria that doubles in size every twenty minutes. The initial population count was 1350 bacteria. Rounding to five significant digits, write an exponential equation representing this situation. To the nearest whole number, what is the population size after 3 hours?
A guy wire for a suspension bridge runs from the ground diagonally to the top of the closest pylon to make a triangle. We can use the Pythagorean Theorem to find the length of guy wire needed. The square of the distance between the wire on the ground and the pylon on the ground is 90,000 feet. The square of the height of the pylon is 160,000 feet. So, the length of the guy wire can be found by evaluating √(90000+160000). What is the length of the guy wire?