For a Doctor's Office, the Processing of Forms in Order

For a doctor's office, the processing of forms in order to receive payment is a necessary part of doing business. If a form is filled out incorrectly, the form can not be processes and is considered defective. Within each office, an individual is responsible for inspecting and correcting the forms before filing them with the appropriate insurance company. Every week, a particular doctor's office samples 20 forms and creates a p chart to monitor how many forms have mistakes. They plan on using this information to justify changing the form. Create a p control chart. What is the process capability? Should they change the form?