Physical Sciences
Once a PVC pipe joint is assembled using solvent cement, a certain amount of time must be allowed for the new joint to set. For 4- to 8-inch-diameter pipes, suppose the setting time (y, measured in hours) is linearly related to the ambient temperature (x, measured in °F). The true regression line is assumed to be y = 8.3 - 0.09x.
a. Find an estimate of an observed setting time for an ambient temperature of 65°F.
b. How much less time does a joint take to set if the temperature rises by 10°F?
c. If σ = 15 minutes, find the probability that an observed set time is less than one hour if the ambient temperature is 80°F.