A reaction time to a certain stimulus (e.g., time until solving some problem) is modeled as a time of completion of r processes, running one after another in a specified order. The times τ1, ...,τr of completion of these processes are assumed to be iid exponential with mean 1/λ. If r = 3 and the observed reaction times of completion of these three processes (in seconds) are 15.3, 6.1, 8.5, and 9.0, test the hypothesis H0 : λ ≥ 0.8 against the alternative H1 : λ < 0.8. Use α = 0.05.