Hello, I'm working on setting new performance goals for my business
group. The metric I'm working on is average talk time for a customer
service call. The goal would be to end the month equal or lower than
the goal. Below is the data for the past 13 months:
5.48 5.61 5.70 6.09 6.13 5.80 5.64 5.63 5.72 5.81 5.91 5.98 5.99


I need to create a formula that will calculate a new target goal that
will have an 80% probability of being successful based on the
historical data for the past 13 months.

Any help would be greatly appreciated. If you have any questions or
need more data, please respond to this post and I can review ASAP.