Question

A coin is tossed 5 times.

What is the probability of getting all heads? Express your answer as a simplified fraction or a decimal rounded to four decimal places.

Answer 1

Let X = Number of heads in 5 trials. Thus possible values of X are 0,1,2,3,4,5

p = probability of getting head = 0.5

n = number of trial = 5

X follows binomial distribution with parameter n and p. PMF of X is

Now we find probability of getting zero heads.

Similarly we find all probabilies.

Probability distribution of X is,

X	0	1	2	3	4	5
P(X)	0.0312	0.1562	0.3125	0.3125	0.1562	0.0312