A fair coin should land showing tails with a relative frequency of 50% in a long series of flips. Felicia read

that spinning-rather than flipping-a US penny on a flat surface is not fair, and that spinning a penny

makes it more likely to land showing tails. She spun her own penny 100 times to test this, and the penny

landed showing tails in 60% of the spins.

Let p represent the proportion of spins that this penny would land showing tails.