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Issues with calculated formula questions

Question asked by richardprince@manchester on Aug 30, 2019
Latest reply on Sep 12, 2019 by smachaje

Hi everyone,

I am trying to use the calculated formula question type and have run into a problem. In theory, the question should allow students to enter an answer either +/- a % or +/- an absolute value. However, Blackboard also seems to require students to use the same number of significant figures that the answer is calculated to. For example, with 5% precision, if the answer to a question is 1.49, then 1.47 is marked as correct because it is within 5%. However, 1.5 is marked incorrect as it is only 2 significant figures. The correct answer feedback given to students though, indicates that this answer should be correct: 1.49 +/- 5%.

If you decide to go with an absolute (numeric) value answer range, then there is an issue with numbers that are smaller than 0.01: the answer range box does not seem to recognise exponential notation and rounds numbers like 1E-7 to zero. This problem also exists on the next dialog page where the calculated answer is rounded to zero if it is less than 0.01 and "normal" rather than exponential answer format is chosen. Basically I think the issue is that Blackboard have not implemented the concept of significant figures correctly here.

I think numerical question format might work correctly for what I am trying to do (rather than the calculated formula format) but the disadvantage of the former is that it does not have an option for students to include units.

Sorry for the long rambling post

Richard University of Manchester UK

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