probability

Not a good question because the probability of one student wearing glasses is not 1/2. This is a medical statistical issue. The probability of a student wearing glasses is not random.

2012-11-18 10:58:11 補充：
As a math question, the randomness of students wearing glasses must be assumed or that probability given before proceeding with calculation.

2012-11-18 11:03:00 補充：
What is "at most" one of the five students not wearing glasses?

Does it mean 0 or 1 student not wearing glasses? If this is the case, the question should state explicitly instead of using the expression "at most 1".

2012-11-18 11:18:17 補充：
Assume the probability of a student wearing glasses is 1/2.

To find the probability that at most one of the five students not wearing glasses is to find the probability of 0 or 1 student not wearing glasses.

Probability of 0 student not wearing glasses
= 1/2 * 1/2 * 1/2 * 1/2 * 1/2 = 1/32

Probability of 1 student not wearing glasses
= 5/32 (because any one of the five students may not wear glasses)

Probability of at most one student not wearing glasses
= 1/32 + 5/32 = 6/32 = 3/16

P( one of the five students not wearing glasses)
=( 1/2 x1/2 x 1/2 /1/2 x1/2) X2
=1/16

2012-11-17 18:54:12 補充：
計probability可以列左表之後再計^^