Second, there was a reduction in terms of the misconceptions used after the teaching
intervention. All the fourteen groups of misconceptions except groups 13 (misused or extended
conclusions inappropriately) reported in the main study were also observed in the teaching
experiment. Equiprobability, chance cannot be measured mathematically, the outcome approach
and own methods in chance comparison (the compound approach is one of the methods) were the
most common misconceptions prior to the teaching intervention. Equiprobability, outcome
approach, own methods in chance comparison and own methods in chance calculation were the
most common misconceptions after the teaching intervention. Although, equiprobability, outcome
approach and own methods of chance comparison were still the most common, they all occurred
less often after the teaching intervention. The percentage of students who used them decreased from
61% to 43%, from 53% to 37% and from 35% to 31%, respectively. The misconceptions of chance
cannot be measured mathematically, subjective judgements and example-based interpretations for
possible and impossible were easily overcome. After the teaching intervention, the percentage of
students who used them decreased from 59% to 12%, from 14% to 2% and from 31% to 4%,
respectively. Third, there was an increase in terms of the developmental level of thinking as
determined by the SOLO analysis of responses.