Fix typo

src/guides/bioinformatics/filtering-and-subsampling.rst

@@ -114,7 +114,7 @@ Subsampling within ``augur filter``
    Subsampling is applied after all standard filter options and before
    force-inclusive filter options.
 
-Another common filtering operation is subsetting of data to a achieve a more
+Another common filtering operation is subsetting of data to achieve a more
 even spatio-temporal distribution or to cut-down data set size to more
 manageable numbers. The filter command allows you to partition the data into
 groups based on column values and sample uniformly. For example, target one