Error in 'normrnd'

I am having the following issue while running this code:

 slam
Undefined function 'normrnd' for input arguments of type 'double'.

Error in moveParticle (line 25)
  speed    = normrnd(movement(1), variance(1)*.25);

Error in slam (line 81)
  real_position = moveParticle(real_position, movement_command, movement_variance);

I am using MATLAB R2013a on Windows 7
