Types of Association
Trend Lines
Interpolation and Extrapolation
Linear Regressions
What Does It Mean?
100
Positive, negative, or no association?
positive
100
Why is this a bad trend line?
it doesn't follow the trend
100
The scatter plot shows the association between minutes played and points scored. Would predicting the points scored for 30 minutes played be an example of interpolation or extrapolation?
interpolation
100
Determine the linear regression equation of the data. Round values to the nearest hundredth.
y = .52x + 14.23
(keep this data for later)
100
What kind of data is the arrow pointing to, and what does it mean?
it is an outlier, does not follow the other data
200
Strong or weak?
weak
200
Which trend line is best?
C
200
The relationship between outdoor temperatures and ice cream sales can be modeled by the equation y = 35x - 250. Predict sales, in dollars, when the temperature is 20 degrees C.
$450
200
Determine the correlation coefficient to the nearest hundredth. What does this number mean?
0.99, a strong positive correlation
200
A linear regression equation has an r-value of 0.04. What does this mean?
There is no correlation.
300
Linear, nonlinear, or no association?
nonlinear
300
Find the equation of the trend line.
y = 1/3x + 40
300
The amount of money earned for hours of babysitting can be modeled by the equation y = 1.5x + 1. Predict the absurd amount earned, in dollars, for 12 hours of babysitting.
$19
300
Determine the linear regression equation for the data. Round values to the nearest hundredth.
y = -3.75x + 90.76
(keep this data for later)
300
What does the point (88, 450) mean on this scatter plot?
When the temperature was 88 degrees, there were 450 beach visitors.
400
How are the associations in these scatter plots DIFFERENT?
one is strong and one is weak
400
Find the equation of the trend line.
y = x
400
The amount of the water bill for various amounts of water used can be modeled by the equation y = 1.75x + 12. Predict the amount of water one can use for a $26 water bill.
8,000 gallons
400
Determine the correlation coefficient for the data to the nearest hundredth. What does this number mean?
-0.96, there is a strong negative correlation
400
Describe the association in terms of the variables: "As cholesterol consumption..."
As cholesterol consumption increases, life expectancy decreases.
500
THREE answers required:
Positive or negative? Linear or nonlinear? Strong or weak?
Negative, linear, strong
500
Find the equation of the trend line.
y = -2x + 40
500
The percent of respondents who listen to online radio since 2007 can be modeled by the equation y = 4x + 18. Predict the year that listenership will reach 70%.
2020
500
Determine the linear regression equation for the data. Is this equation a good model for the data, and why?
y = -0.15x + 7.27
no, the r-value is only -0.18
500
The linear regression equation for the scatter plot is y = 635x + 20,000. What does the slope and the y-intercept represent in terms of the variables?
The population increases 635 people per year. The population was 20,000 in 1900.