Average Standard Deviation Of Array Within Matrix

I have tried to find information on this subject, but it seems diifficult to find exactly what I am looking for. I have provided a test example of the operation that I would like to acheive. The first example (Method 1) works well enough but would require defining more detailed functions beyond the scope of average. This would probably be ok, but more importantly, I would like to source particular arrays in this manner for other tasks beyond averages and even standard deviation and am not quite sure how this can be done. In an attempt to describe the situation, I have provided a second example (Method 2). In this example, I am trying to take the average of the jth column array to create an array of averages. I am not sure if I am incorrectly setting up the matrix, if the functions don't perform this way in the matrix, or if this is simply not possible.

Sub test()
a = 5
b = 5
Redim X(1 To a, 1 To b) As Double
'Assumes there is a matrix of values [a x b] drawn from worksheet
For j = 1 To b
For i = 1 To a
X(i, j) = Cells(i, j)
Next
Next

'----METHOD 1---------------------------------------------
'I know this way works using average as an example, but...
Redim AverageX(1 To a, 1 To b) As Double.......................