Which is the correct formula for median of grouped data?
Consider:
L = lower limit of median class
CF0 = cumulative frequency of preceding class
F = frequency of median class
H = class width
N = the total of frequency
1
\(\frac{{\frac{{\rm{N}}}{{\rm{2}}}{\rm{ - }}\,{\rm{C}}{{\rm{F}}_{\rm{0}}}}}{{\rm{F}}}{\rm{ \times }}\,{\rm{H}}\)
2
\({\rm{L}}\,{\rm{ + }}\,\frac{{\rm{N}}}{{\rm{2}}}\,\,{\rm{ - }}\,\,{\rm{C}}{{\rm{F}}_{\rm{0}}}{\rm{ - F}}\,{\rm{ \times }}\,{\rm{H}}\)
3
\({\rm{L}}\,{\rm{ + }}\,\frac{{\frac{{\rm{N}}}{{\rm{2}}}\,\,{\rm{ - }}\,\,{\rm{C}}{{\rm{F}}_{\rm{0}}}}}{{\rm{F}}}\,{\rm{ \times }}\,{\rm{H}}\)
4
\({\rm{L}}\,{\rm{ + }}\,\frac{{\frac{{\rm{N}}}{{\rm{2}}}\,\,{\rm{ - }}\,\,{\rm{C}}{{\rm{F}}_{\rm{0}}}}}{{\rm{F}}}\)