Interpreting Physics Grade Sheet: Percentile, Mean%, & SD Explained

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Discussion Overview

The discussion revolves around interpreting a physics grade sheet, specifically focusing on understanding the Percentile, Mean%, and Standard Deviation (SD) values presented in the context of quiz performance. Participants are exploring the implications of these statistics for individual standing in relation to classmates.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks clarification on the meaning of Percentile, Mean%, and SD in their grade sheet, expressing confusion about their performance relative to peers.
  • Another participant explains that the Percentile indicates the percentage of students scored below the individual, suggesting that the individual performed better than 58% of their classmates, while also noting the small class size.
  • A participant questions the standard deviation, asking if 66% is a typical range and points out that their class has 26 students, which may affect the interpretation of the statistics.
  • Further clarification is provided regarding the interpretation of the grade sheet, with a participant suggesting that the Percentile may have been miscalculated based on the number of students in the class, proposing a new interpretation that places the individual in the 4th percentile.
  • There is a discussion about whether the SD is expressed in percentage or points, with one participant noting that it seems broad given the quiz's total points.
  • One participant mentions that 1 standard deviation typically encompasses 66% of the data points around the mean, encouraging further research on the topic.

Areas of Agreement / Disagreement

Participants express differing interpretations of the grade sheet statistics, particularly regarding the calculation of the Percentile and the understanding of Standard Deviation. There is no consensus on the correct interpretation, and the discussion remains unresolved.

Contextual Notes

Participants are working with potentially incomplete information regarding the definitions and calculations of the statistics presented in the grade sheet. The assumptions about class size and the nature of the SD are not fully clarified.

barcat
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I was wondering if someone could help me interpret a grade sheet I got in physics? Below is a slip that I received after our last quiz.
I understand what the first three columns are, but the Percentile, Mean%, and SD is what is comfusing me. I really do not know where I stand, in this class, compared to the rest of my fellow students.

I tried to copy this to a post, but I would not take. Below is the attatchment.
barry

Quiz Individual Performance GroupPerformance
Max. Score Score(%) Percentile N Mean(%) SD
Quiz 40 36.50 91.25% 42 6 85.63% 11.88
Total 40 36.5 91.3% 42 6 85.6% 11.9
 
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Your precential means that you did better the 58% of the people taking the test, N could/should be the number taking the test (6? pretty small class!) SD is the standard deviation, 66% of the scores fall within 1 SD of the mean. For this test 66% of the scores fell between 96% and 84%
 
Integral, thanks for the response. Is there a better way that I
could have posted the bottom part of my request?
I tried to attatch a DOC image, but it would'nt take.

Is 66% a standard for SD? We have 26 students in this class
(internet quizes), I was the first to take it. Also, how did
you arrive at 58%?
barry
 
I read the numbers as

Max. Score Score(%) Percentile N Mean(%) SD
40 36.50 91.25% 42 6 85.63% 11.88
Total 40 36.5 91.3% 42 6 85.6% 11.9

------------Quiz-----Total
Max.------- -40------- 40
Score-------36.5------36.5
Score(%)----91.25%----91.3%
Percentile --42--------42
N-------------6---------6
Mean(%)------85.635----85.6%
SD-----------11.88------11.9

looks like it should read
------------Quiz-----Total
Max.------- -40------- 40
Score-------36.5------36.5
Score(%)----91.25%----91.3%
Percentile --4---------4
N------------26--------26
Mean(%)------85.635----85.6%
SD-----------11.88------11.9

This changes the percentile allot, now you are in the 4th percentile which means you have a better score then 96% of the class


Initially I assumed that the SD was a percent, In reality it may be in points, which seems pretty broad considering it was a 40 point quiz.

1 standard Deviation is defined to be the span around the mean which contains 66% of the things being averaged. You may want to do a web search on the term it is a very commonly used statistic.