YipChun ka 發問於 科學及數學數學 · 3 年前

# 一條數學題目 Get唔到題目想點?

The probability that a person has a particularly rare blood group is p.

Choose a value for p, which should be well below 0.05, and work out the minimum number of people you will need to meet in order to be more likely than not that you will find someone with this blood group.

### 1 個解答

• 3 年前
最愛解答

取一個 p ( < 0.05 ), 求最小的 n 使 P(X > 0) > 1/2?

p = 0.04, (1-p)^n < 1/2, 最小的 n > log(1/2)/log(0.96) = 16.98, n=17

p = 0.03, n > log(0.5)/log(0.97) = 22.76, n=23