Showing results for tags 'guessing'. - Engineer Boards
Jump to content
Engineer Boards

Search the Community

Showing results for tags 'guessing'.

More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • Welcome
    • Introduce Yourself
    • Advertising on engineerboards
  • Vendor Forums
    • EB.COM vendor list
    • Vendor Display
    • Vendor Giveaways / Deals
  • Exam Discussion
    • Anything about the PE Exam
    • PE Exam Results
    • The FE Exam
    • Anything about the RLS Exam
  • PE Exam Prep Forum
    • Civil Engineering PE Exam
    • Mechanical
    • Electrical
    • Environmental Exam
    • Structural
    • Chemical Exam
    • Fire Protection Exam
    • Materials and Metallurgical Engineering
  • Technical Discussions
    • EB.COM Salary Surveys
    • General Engineering
    • Civil Engineering
    • Electrical
    • Mechanical
    • Public Agency Employees
  • General Discussion
    • Shoot the Breeze
  • Swap Shop
    • Job Postings
    • Yard Sale
    • Continuing Education

Product Groups

  • Supporting Member
  • Registered Vendor
  • Banner Advertising
  • Engineerboards stickers


There are no results to display.

There are no results to display.

Find results in...

Find results that contain...

Date Created

  • Start


Last Updated

  • Start


Filter by number of...


  • Start





Website URL







Engineering Field

Found 1 result

  1. So, I was curious what the probability of someone passing the PE exam based on completely random guessing (because it seemed feasible), so, I did some math. The probabilities are based on an assumed passing score of 70% (56/80), using the binomial cumulative probability... that is, for randomly guessing all 80 questions, what's the probability of guessing at least 56 correct? Thus, calculate the binomial cdf for (n=80, p=0.25, and x=56 + x=57 + ...x=80) For all 80 questions, the probability of guessing at least 56 correctly turns out to be 3.64 x 10^-17. That is, 1 in 27,500,000,000,000,000 test takers will be likely to pass the exam with random guessing. However, if a test taker is 100% confident that he worked out half the questions correctly, and wanted to simply guess on the other 40 questions, he would only need to guess 16 problems correctly out of the remaining 40. The probability is calculated similarly, with a binomial cdf of (n=40, p=0.25, and x=16 + x=17....x=40). This turns out to be a probability of 0.026. That is, 1 out of about 50 test takers who definitely answer 40 questions correctly can expect to pass the exam by guessing on the remaining questions. Here's the breakdown: 0 definitely correct, Guess 56/80 correctly to pass : 1 in 27,500,000,000,000,000 will pass(1 out of 27 Quintillion) 10 correct, Guess 46/70: 1 in 1,170,000,000,000 will pass (1 out of a trillion) 20 correct, Guess 36/60: 1 in 103,000,000 will pass 30 correct, Guess 26/50: 1 in 26,300 will pass 40 correct, Guess 16/40: 1 in 50 will pass. 50 correct, Guess 6/30, 4 in 5 will pass. 60 correct ... pretty sure you passed!
  • Create New...