Hi,
The Selection fields can be directly created with the Odoo studio. Drag and drop 'Selection' from the Add > New fields selection and in the field properties popup add the required selection options - 'Yes', 'No', 'Do not apply'.

For the percentage calculation a Decimal(float) field can be used. We have to define a compute function for this float field. For that select the field, cllck on the 'More' option under the Properties tab. In the form view , you can see the options to provide Dependencies and Compute function.

In the dependencies provide the names of the 5 selection fields separated by comma. For example - x_studio_n1, x_studio_n2,x_studio_n3, x_studio_n4,x_studio_n5.
In the Compute field provide the code to calculate our percentage.

Sample Code:

for record in self:
  yes_count = 0
  if record.x_studio_n1 == 'Yes':
    yes_count += 1
  if record.x_studio_n2 == 'Yes':
    yes_count += 1
  if record.x_studio_n3 == 'Yes':
    yes_count += 1
  if record.x_studio_n4 == 'Yes':
    yes_count += 1
  if record.x_studio_n5 == 'Yes':
    yes_count += 1    
  record['x_studio_percentage'] = yes_count*100/5

Regards