Which of the following is more probable?
A. Flipping a coin 4 times and obtaining at least 3 heads.
B. Flipping a coin 5 times and obtaining at least 3 heads.
A) A
B) B
C) same
D) cannot tell

Question

Quizplus · Accepted Answer

The probability of obtaining at least 3 heads in 4 coin flips is calculated as follows:
P(3 heads) + P(4 heads) = [(4 choose 3)(0.5)^3(0.5)^1] + [(4 choose 4)(0.5)^4(0.5)^0] = 0.375
The probability of obtaining at least 3 heads in 5 coin flips is calculated as follows:
P(3 heads) + P(4 heads) + P(5 heads) = [(5 choose 3)(0.5)^3(0.5)^2] + [(5 choose 4)(0.5)^4(0.5)^1] + [(5 choose 5)(0.5)^5(0.5)^0] = 0.5
Therefore, the probability of obtaining at least 3 heads is higher when flipping a coin 5 times.

Which of the Following Is More Probable