We read the values for the quartiles from the graph and arrive at 38 and 47. You are allowed to be out by a little but be as accurate as you can. So the interquartile range is the difference ...

text{biggest number} - \text{smallest number} = 4.1 - 2.5 = 1.6\) The range of weights is 1.6 kg. The interquartile range shows the range in values of the central 50% of the data. To find the ...