Due to improved technology and public-service campaigns, the number of collisions at highway€“railroad crossings per year has declined since 1992 (see Table 52).

Let n be the number of collisions (in thousands) for the year that is t years since 1990.
a. Construct a scatterplot by hand.
b. Draw a linear model on your scatterplot.
c. Use your linear model to estimate the number of collisions in 2012. Did you perform interpolation or extrapolation?
d. Use your linear model to predict in which year there will be 1.0 thousand collisions. Did you perform interpolation or extrapolation? Do you have much faith in your result? Explain.
e. Find the t-intercept. What does it mean in this situation? Do you have much faith in your result? Explain.

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Table 52 Numbers of Collisions at Highway- Railroad Crossings Number of Collisions thousands) 4.9 4.6 3.5 3.1 2.1 2.3 Year 1992 1995 2000 2005 2010 2014