Figure CRF4.2 shows the average reading scores for this group and for year four students in Tonga in previous PILNA cycles. The scores for year four students in Tonga in 2021 were about the same as in 2018 but lower than in 2015. The standard deviation for the average reading scores in 2021 was slightly higher than previous PILNA cycles. This means that the spread of year four overall reading scores was wider than in previous years.

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.