2 consecutive heads

ask students to keep throwing a coin until they get two heads in a row
how many throws does it take to get two heads in a row?

do this several times







from the experimental data, possibly collected from the class, what is the average expected number of throws until you get 2 heads in a row?

the expected value is 6
and this theoretical value can be compared with the (average) of the experimental values obtained

how widely do the experimental values vary?