08:26 Jun 15, 2011
To paraphrase the paragraph,
50% of all travellers – stay less than 4.0 days
50% of all travellers – stay more than 4.0 days
Holiday travellers – stay on average 6 days
“Education segment” – stay on average 125 days
All travellers – stay on average 18.5 days
You really don’t know how many days each type of traveller actually stays in NZ. You only know an average.
If we try plotting these graphs, we might expect the graph of each type of traveller to be roughly symmetrical. However, if we try plotting the graph for all travellers, the “hump” of the graph would be on the far left with a long tail to the right (and possibly a secondary hump on the right somewhere): It will be a very asymmetrical distribution. This is the “skew” that the text is talking about: The long stay of students is “skewing” the average to 18.5; it is a skew in a strict mathematical sense.
PS: I hope my description of the graphs in the last paragraph makes sense. Statistics has never been my strong suit and I could have mixed things up. | 
The translation workplace 
peer agreement (net): +1
