The data below are the average one-way commute times (in minutes) for selected students and the number of absences for those students during the term. Commute time (min.), x Number of absences,

x 45 62 80 85 75 94 70 96 66

y 3 7 9 10 8 14 4 16 5

a. Find the equation of the regression line for the given data. Round the regression line values to the nearest hundredth.

b. What would be the predicted number of absences if the commute time was 95 minutes? Round the predicted number of absences to the nearest whole number.

c. Is this a reasonable question? Explain why or why not.

Farmers know that driving heavy equipment on wet soil compresses the soil and injures future crops. here are data on the "penetrability" of the same type of soil at two levels of compression. penetrability is a measure of how much resistance plant roots will meet when they try to grow through the soil. compressed soil 2.85 2.66 3 2.82 2.76 2.81 2.78 3.08 2.94 2.86 3.08 2.82 2.78 2.98 3.00 2.78 2.96 2.90 3.18 3.16 intermediate soil 3.17 3.37 3.1 3.40 3.38 3.14 3.18 3.26 2.96 3.02 3.54 3.36 3.18 3.12 3.86 2.92 3.46 3.44 3.62 4.26 use the data, omitting the high outlier, to give a 95% confidence interval for the decrease in penetrability of compressed soil relative to intermediate soil. compute degrees of freedom using the conservative method. interval: to