Probability Problem
2014-05-06 8:07 pm
An exam paper consists of 100 multiple-choice questions, each with 4 different choices. One mark is scored for a correct answer. The examiner wants to set the passing mark simply by consideration that if a student chooses an answer choice randomly for every question, he will only have 5% chance of passing the examination. What would be the passing mark?
回答 (3)
2014-05-07 2:11 am
✔ 最佳答案
Using Excel,We put the first column 100,99,98,97,...,1.
We put the second column a formula: COMBIN(100,A1)*0.25^A1*0.75^(100-A1) and pull down the bottom-right square to the last row.
We then scroll the second column and see the summation of the numbers you have chosen in the bottom right hand corner. Then you can see that if the passing mark is 33, the summation is 0.04459...... but if the passing mark is 32, the summation is 0.069348... so I think the answer to your question is 33.
參考: Excel
2014-05-07 5:46 am
this is an exam question.
no computer software is allowed to use.
normal approximation is a good method to solve.
no computer software is allowed to use.
normal approximation is a good method to solve.
2014-05-07 3:32 am
亦可試用 normal approximation 。
收錄日期: 2021-04-18 14:00:45
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