Figure CNF6.2 shows the average numeracy scores of this group and of year six students in Tonga in previous PILNA cycles. The average overall numeracy score for these students in 2021 was lower than in the 2018 PILNA cycle, but higher than in the 2015 PILNA cycle. The standard deviation for the 2021 cycle was similar to that of previous PILNA cycles. This means that the spread of year six overall numeracy scores in 2021 was similar to that of previous PILNA cycles. More analysis needs to be done to understand whether these differences in scores are statistically significant.

Standard deviation shows how close data points are to the average. A lower standard deviation means that data points are, overall, closer to the average; a higher standard deviation means that data points are, overall, further away from the average.