Each of your rows has 30 NaN values.
In rows 1 and 2, they are in columns 95221 to 95250.
In rows 3 and 4, they are in columns 94951 to 94980 .
mean() of a value that includes nan is going to be nan, because anything added to nan gives nan as a result.
You can use
mu = mean(XV, 2, 'omitnan');
sg = std(XV, , 2, 'omitnan');