Draw a tree diagram to display all the possible head-tail sequences that can occur when you flip a coin three times. How many sequences contain exactly two heads? Assuming the sequences are all...

Draw a tree diagram to display all the possible head-tail sequences that can occur when you flip a coin three times. How many sequences contain exactly two heads? Assuming the sequences are all equally likely, what is the probability that you will get exactly two heads when you toss a coin three times?