A fair coin is flipped 100 times independently Our interest

A fair coin is flipped 100 times independently. Our interest is on X, the total number of heads in this experiment. What is the probability distribution of X? Binomial Normal Not enough information What is the approximate probability that X

Solution

24. As, the outcomes are discrete, can only take value as \"Head\" or \" tail\"..and prob. for each trail is same,
this is a) Binomial!

25) MEAN = n*p = 100* 0.5 =50
s.d = sqrt ( 100* 0.5 * 0.5) = 5.....

P [ X < 40 ] = P [ Z < ( 40 - 50) / 5 ]
= P [ z < -2 ] = 0.0027..........

26) P [ X > 55 ] = P [ Z > ( 55-50) /5 ] = P [ Z > 1]
= 1 - P [ Z < 1 ] = 1 - 0.8413 = 0.1587....