dolphinitida wrote:
For III - Since the data is for 11 consecutive years, why can't you consider year 6 (1990) as the mean? If you do, the annual income appears to be right under $40,000.
What you are talking about is the median. Year 6 will give you the median income. The mean needn't lie at the middle value.
Say, for a set of numbers 4, 5, 5, 6, 7, 20, 22, mean will not be 6 (the middle value). Median will be 6 but mean will be much higher.
Another way to analyze statement III is this:
First 3 points are at most 15000 less than 40,000.
Next 4 points are almost 40,000 each.
The next point is at least 15,000 more than 40,000
The next 3 points are at least 20,000 more than 40,000.
So overall, the distance of the points higher than 40,000 is more than the distance of the points lower than 40,000. This is just your deviation concept applied visually.
For more on deviation, check:
http://www.veritasprep.com/blog/2012/05 ... eviations/this saves a lot of time. i kept addiing all the values and calculating average, eating lot of time
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