Both mean and median are measures of the center of a set of data.
Mean is normally preffered to the median except if there is an outlier that has a tendency to affect the mean.
An outlier is a data point that significantly differs from the other data points in a sample.
In the data set above, there is no outlier that will affect the mean.
Therefore, he should use the mean because there are no outliers that affect the mean.
Answer:
the last one is the answer of it
There really is no single "obvious" choice here...
Possibly the sequence is periodic, with seven copies of -1 followed by six copies of 0, or perhaps seven -1s and seven 0s. Or maybe seven -1s, followed by six 0s, then five 1s, and so on, but after a certain point it would seem we have to have negative copies of a number, which is meaningless.
Or maybe it's not periodic, and every seventh value in the sequence is incremented by 1? Who knows?
I'll go ahead and assume the latter case, that the sequence is not periodic, since that's technically somewhat easier to manage. We can assign the following rule to the

-th term in the sequence:


for

.
So the generating function for this sequence might be

As to what is meant by "closed form", I'm not sure. Would this answer be acceptable? Or do you need to find a possibly more tractable form for the coefficient not in terms of the floor function?
Start by mult. both 0.4 and 5.12 by 100. What is 40 divided by 512?
___.078_______________
512 / 40.000
3584
-----------
4160
4096
---------
64 and so on. Calculator answer is 0.078125.