hahah, I can tell you -- have been doing (cursed) mean/ median and mode all year with my tutees. Mean is average; mode is the number that occurs most frequently in a data set; median is the middle number in a data set, or the average of the two middle, if there are two.
We tutors roll our eyes about these -- you can end up looking like an idiot when it comes up, because WHO ever uses these things?
This was not even one of those terms. And I do think the test book is off. aaahhhhh. Six of the questions of 40 were on this one thing, and I would have missed them all.
Perhaps thinking of a highway median running right down the middle and remembering that the words 'mode' and 'most' both start with the same letters will help me keep them straight. You're right, though, who ever uses these things in 'ordinary' life?