Google-sheets – googleFinance calculating the standard deviation of a stock over a time period

No, it is not possible. You can however just reference the lower right cell in another cell.

so if you got back from Google:

A1: "Date"      B1: "Close"
A2: "3/3/2000"  B2: "55.22"
A3: "Date"      B3: "Close"
A4: "3/4/2000"  B4: "58.44"

Set cell C1 =B2 and cell C2 =B4

and the results will be:

C1: 55.22
C2: 58.44

you could also put the query in one google doc and then reference it from another google doc if you really wanted to separete the data.

I'll describe the process in stages. Here is a command that returns a table with high price on every day within the last 26 weeks:

=GOOGLEFINANCE("GOOG","high",TODAY()-26*7,TODAY())

Output:

+-------------------+----------+
|       Date        |   High   |
+-------------------+----------+
| 2/2/2015 16:00:00 | 533      |
| 2/3/2015 16:00:00 | 533.4    |
| ................. | .......  | 

Since you only want the maximum of these numbers, let's add a QUERY selecting the maximum of the second column:

=QUERY(GOOGLEFINANCE("GOOG","high",TODAY()-26*7,TODAY()),"select max(Col2)")

Output:

+----------+
| max High |
+----------+
| 678.64   |
+----------+

This may be already good enough for your purposes. If you want to get rid of the column header "max High", end the query string with label max(Col2) '':

=QUERY(GOOGLEFINANCE("GOOG","high",TODAY()-26*7,TODAY()),"select max(Col2) label max(Col2) ''")

Output:

+----------+
| 678.64   |
+----------+