<prompt> Translate the following text to EnglishLongitudinal data ni data ya mfululizo wa muda, ambayo ni pamoja na uchunguzi wa muda mrefu, na sampuli ya sampuli inaweza kuwa sawa au isiyo sawa kila wakati.  <response>: Longitudinal Data Sometimes called time series data, observations collected over a period of time; the sample instances or cases may or may not be the same each time. 