how can I apply low pass filter to a time series data

hi i have a set of random data which is actually a time series data stored in a file. i want to apply low pass filter or high pass filter to such stored data. can anyone please tell me the method to do this work.

Answer 1

[Rick Rosson]

   >> doc fdatool
   >> doc filter
   >> doc designfilt

[Rizwana Junaid]

thank you sir

[Rick Rosson]

One more:

   >> doc fvtool

Answer 2

[Chad Greene]

If you have the signal processing toolbox, this makes the process a little bit easier: http://www.mathworks.com/matlabcentral/fileexchange/38584-butterworth-filters

[Rizwana Junaid]

thank you chad