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mrb
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This is from the practice Math Subject GRE 0568, problem 44.
A fair coin is to be tossed 100 times, with each toss resulting in a head or a tail. If H is total the number of heads and T is the total number of tails, which of the following events has the greatest probability?
(A) [tex]H = 50 [/tex]
(B) [tex]T \ge 60 [/tex]
(C) [tex]51 \le H \le 55 [/tex]
(D) [tex]H \ge 48 [/tex] and [tex]T \ge 48[/tex]
(E) [tex]H \le 5 [/tex] or [tex]H \ge 95 [/tex]
Well, I can set up expressions that give the probabilities. For instance, (A) is obviously
[tex] \binom{100}{50}(1/2)^{100} [/tex]
And (B) just involves summing similar terms for values 60 through 100. But how to compare these? It's not too hard to figure out that A, C, or E can't be right, but how do I compare B vs. D? Another Math Subject GRE practice test I have has a similar problem.
Thanks.
Homework Statement
A fair coin is to be tossed 100 times, with each toss resulting in a head or a tail. If H is total the number of heads and T is the total number of tails, which of the following events has the greatest probability?
(A) [tex]H = 50 [/tex]
(B) [tex]T \ge 60 [/tex]
(C) [tex]51 \le H \le 55 [/tex]
(D) [tex]H \ge 48 [/tex] and [tex]T \ge 48[/tex]
(E) [tex]H \le 5 [/tex] or [tex]H \ge 95 [/tex]
Homework Equations
The Attempt at a Solution
Well, I can set up expressions that give the probabilities. For instance, (A) is obviously
[tex] \binom{100}{50}(1/2)^{100} [/tex]
And (B) just involves summing similar terms for values 60 through 100. But how to compare these? It's not too hard to figure out that A, C, or E can't be right, but how do I compare B vs. D? Another Math Subject GRE practice test I have has a similar problem.
Thanks.
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