First, LuLu was not a hard worker and was fired, replaced with a self-check-in process (check-in takes no time). Second, it was discovered that even though customers had appointments every 10 minutes, it turned out that they do not arrive punctually. Experience shows that customers arrive every 10 minutes on average, but the standard deviation of inter-arrival times is also 10 minutes (CV = 1). Also, the 3 stylists François, Bernard, and Mimi still require 25 minutes on average to take care of a customer, but this time varies from customer to customer with standard deviation 25 minutes (CV = 1). There are things managers can do to improve business processes to reduce customer waiting. Which of the following operational and marketing levers have the potential to reduce the average customer waiting time? (There are multiple correct answers and partial credit is available.)

a. Install a 4th salon chair and hire a 4th hair stylist (i. e., increase hair stylist capacity 33%).
b. Create a smartphone reminder app that gets customers to arrive on time (i. e., reduce inter-arrival time variability so that CVa is less than 1).
c. Reduce the average inter-arrival time of customers from every 10 minutes to every 8 minutes.
d. Raise the price of hairstyles to scale back customer demand (and effectively have customers arrive less often than 1 every 10 minutes).
e. Teach the 3 hairstylists to work more consistently so that each customer contact is closer to 25 minutes (i. e., make CVp less than 1).
f. Teach the 3 hairstylists to work faster (i. e., so that their average service time is less than 25 minutes).