Consider n independent flips of a coin having probability p of landing on heads. Say that a changeover occurs whenever an outcome differs from the...

Consider n independent flips of a coin having probability p of landing on heads. Say that a changeover occurs whenever an outcome differs from the one preceding it. For instance, in n=5 and the outcome HHTHT, then there are 3 changeovers. Find the expected number, variance and generating function of changeovers.