Refer to problem 23. In addition to the information provided in the problem, Patient Transport Co. has also specified an upper tolerance limit of 20 minutes for its transportation time.

1. Is the company achieving Six Sigma–level quality?

2. If not, how should it do so?

Data from problems 23

The fictional Patient Transport Co.’s target time to get customers to hospitals is 16 minutes. To evaluate whether it is reaching that target, for 20 consecutive days, the firm tracked patients’ actual times to the hospital using sample sizes of n = 5 each day. Using the sample data, the company estimated the mean of the process to be X̅ = 19.8 minutes and the standard deviation to be s = 8.5 minutes. Assume that the process is normally distributed and that the mean and range charts for it indicate it is in control. Using the Taguchi-loss function, comment on the efficiency of the process and make specific recommendations for its improvement.