I have a code that loops through and does some computation on 5 random values from my lists of data (2187 rows long). for i = 1:3 randomdata = round(rand(5,1).*2187); xval = x(randomdata) yval = y(randomdata) numerator = length(xval).*nansum(xval.*yval) - (nansum(xval).*nansum(yval)) end my output on the screen is as follows: 5 random values stored in xval & yval xval = 3.3 3.2 6.4 4.3 1.2 yval = 13 33 83 42 9 numerator = -.34 numerator = -.12 numerator = -.45 My question is why isnt numerator being stored as a 5x1 array like xval and yval??