Bina selang kelas. Lazimnya nilai had bawah kelas yang pertama ialah nilai cerapan yang minimum @ boleh ambil nilai yang kurang dari nilai cerapan minimum yang bersesuaian
Build a class interval. Typically the bottom limit value class first is the observation valueminimum @ can take a value less than the minimum value of the observations that are appropriate
Build class interval. Typically, the lower limit of the first class is the observation that the minimum @ can take less than an appropriate minimum observed value