More on significant figures

I’ve said before that students are not good at giving answers to an appropriate number of significant figures. But what do they do wrong? The question shown on the left provides some insight.

The correct three options are B, C and E and they are the three most commonly selected. However options C and E are selected more frequently than option B. The two incorrect responses are selected an approproximately equal number of times – perhaps due to guessing; this question is in formative-only use.

Things get more interesting when you just look at responses from students who use all three responses before getting the question right – or who fail to get it right at all. Whilst 69.2% of these responses include Option C and 65.1% include Option E, only 56.4% include Option B – and an almost identical proportion of responses (56.0%) include the incorrect Option A. So leading and trailing zeroes cause problems.

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