A school recorded the number of times pupils were late each month. Colin says 'the number of lates in March was half that in January.' is he correct? Show how you know

No he is incorrect. If you look at the graph the first set starts 20 and continues by increments of 10. Although it looks like it is half of you follow the graph you can see match had a total of 20 lates. In January it was 30. If it was half like he believes it would be 15 lates in January not 20 he is incorrect.