A small hair salon in Denver, Colorado, averages about 45 customers on weekdays with a standard deviation of 6. It is safe to assume that the underlying distribution is normal. In an attempt to increase the number of weekday customers, the manager offers a $5 discount on 2 consecutive weekdays. She reports that her strategy has worked since the sample mean of customers during this 2 weekday period jumps to 54. Use Table 1.
a. What is the probability to get a sample average of 54 or more customers if the manager had not offered the discount? (Round "z" value to 2 decimal places, and final answer to 4 decimal places.)