Question 862259
p = .5,  n = 4
{{{P (1)= highlight_green(4C1)(.5^1)(.5)^(3) }}} = .25
{{{P (0)= highlight_green(4C0)(.5^0)(.5)^(4) }}} = .0625
P(one call  0r no call) = P(1) + P(0) = .3125