Use the dataset old faithful on the companion website; it gives data for n = 299 eruptions of the Old Faithful geyser. The variable Duration is the duration (minutes) of an eruption, and the variable TimeNext is the time interval (minutes) until the next eruption.
a. Plot Time Next (y) versus Duration (x). Describe the direction and strength of the relationship, and comment on whether there are any outliers.
b. Determine the equation of the regression line relating y = Time Next to x = Duration. Write the equation.
c. What is the value of the slope of the equation? Write a sentence that interprets the slope in the context of these variables.
d. Estimate the interval of time until the next eruption following one that lasts 4 minutes.