Suppose we want to prove that a digital sign outside our firm's restaurants will draw in more customers than the standard outdoor signage. To test this out, we count the daily customers at 12 of our restaurants for one week using the standard signage, and then we count the customers at these same 12 restaurants for one week with the new digital signage. Assume the daily restaurant attendance is distributed normal and that distribution doesn't vary from day to day.

What is the degrees of freedom for this test?

	a.	23
	b.	22
	c.	12
	d.	11