ST102_2017_LT0_commentary.pdf

You are not expected to write long essays where

This preview shows page 1 - 3 out of 6 pages.

You are not expected to write long essays where explanations or descriptions are required, and note-form answers are acceptable. However, clear and accurate language, both mathematical and written, is expected and marked. 1
Image of page 1

Subscribe to view the full document.

ST102 Elementary Statistical Theory (LT0 examination) Key steps to improvement The most important thing you can do is answer the question set! This may sound very simple, but these are some of the things that candidates did not do. Remember: Always show your working. The bulk of the marks are awarded for your approach, rather than the final answer. Write legibly! Keep solutions to the same question in one place. Avoid scattering your solutions randomly throughout the answer booklet — the Examiners will not appreciate having to spend a lot of time searching for different elements of your solutions. Where appropriate, underline your final answer. Do not waste time calculating things which are not required by the Examiners! Using the commentary We hope that you find the commentary useful. For each question and subquestion, it gives: the answers, or keys to the answers, which the Examiners were looking for common mistakes, as identified by the Examiners. Student performance by question Question # Number of Mean Score Std. deviation attempts 1 610 14.21 6.77 2 610 20.78 5.24 Q1 Q2 0 5 10 15 20 25 Boxplots of student performance by question Marks Dr James Abdey, ST102 Lecturer, February 2017 2
Image of page 2
Examiners’ commentaries 2017 Examiners’ commentary 2017 ST102 Elementary Statistical Theory (LT0 examination) Specific comments on questions Question 1 (a) Feedback on this question: An unseen question – the famous ‘boy or girl paradox’. Most candidates failed to realise the simplicity of this exercise either using independence (ignoring the conditionality) or did not treat (Boy, Girl) and (Girl, Boy) as distinct observations. Credit was lost when Bayes’ theorem was used with the complete formula, but with the wrong conditional probability. Full solutions are as follows.
Image of page 3
You've reached the end of this preview.
  • Fall '15
  • Probability theory, Elementary Statistical Theory

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern