A customer service area at a retail store processes returns, answers customer questions and addresses customer complaints. The manager of the store believes that if customers wait more than $8$ minutes to get a customer service representative, they get irritated. The customer service process has been designed to achieve a customer wait time of between $6$ and $12$ minutes. The manager has collected $10$ samples of $5$ observations each of customer waiting time over a two$-$week period. The data of the waiting times is given in the following table: