Suppose we want something simple, like the number of heads in 3 tosses of a coin. We list the outcomes and count those of interest. For our coin toss example, know the choices are

t t t - 0 heads

t t h - 1 head

t h t - 1 head

t h h - 2 heads

h t t - 1 head

h t h - 2 heads

h h t - 2 heads

h h h - 3 heads

Because it is easier here, we will create the distribution "sideways". Down the side, we will list the number of heads. Across we will show the probability as a bar indicating the number of instances. At the end of the bar, we will show the probability of that number of heads in 3 tosses.

N | P(N heads in 3 tosses)

0 | x (1/8)

1 | x x x (3/8)

2 | x x x (3/8)

3 | x (1/8)

With a little more effort, one can use the graphing capabilities of spreadsheet software to create a more conventional distribution graph.

t t t - 0 heads

t t h - 1 head

t h t - 1 head

t h h - 2 heads

h t t - 1 head

h t h - 2 heads

h h t - 2 heads

h h h - 3 heads

Because it is easier here, we will create the distribution "sideways". Down the side, we will list the number of heads. Across we will show the probability as a bar indicating the number of instances. At the end of the bar, we will show the probability of that number of heads in 3 tosses.

N | P(N heads in 3 tosses)

0 | x (1/8)

1 | x x x (3/8)

2 | x x x (3/8)

3 | x (1/8)

With a little more effort, one can use the graphing capabilities of spreadsheet software to create a more conventional distribution graph.