Question

If a fair coin is tossed three times the probability function p(x) of the number of heads x is _______

(a) 

X	0	1	2	3
P(x)	1/8	1/8	2/8	3/8

(b) 

X	0	1	2	3
p(x)	1/8	3/8	3/8	1/8

(c) 

X	0	1	2	3
p(x)	1/8	1/8	2/8	3/8

(d) None of these

Answer 1

(b) 

X	0	1	2	3
p(x)	1/8	3/8	3/8	1/8

The sample space is HHH, HHT, HTH, HTT, THH, THT, TTH and TTT 

Number of heads is 0, 1, 2, 3 with probability 1/8, 3/8, 3/8 and 1/8