Probability Question

CFA Level I
#1

If John tosses a two sided coin 6 times, which of the following is closest to the probability of obtaining exactly 3 heads ? A) 0.02 B) 0.16 C) 0.31 D) 1.88

#2

C 6c3 * .5 ^ 6 = .3125

#3

nm

#4

cpk, could u pls explain how u get solve for 6c3? I know it’s such a dumbo question. Also, pls state the name of this theory or concept. Thanks.

#5
  1. this is application of the binomial concept. 2. for 6c3 in mathematical terms -> nCr ==> number of ways of choosing r things out of n, where the ORDER of r does not matter. = n! / (r! * (n-r)!) do not worry about this above. If you have the TI BA calc. Press 6 2nd + 3 = gives you the answer = 20.
#6

Or Total # of outcomes - 2^6=64 Outcomes for exactly 3 head - 6c3=20 Prob=20/64 = 0.3125

#7

Tks cpk and goel_ar. It’s very helpful.