CHAPTER 7: STATISTICS

PREVIOUS KNOWLEDGE

• Median For Grouped Data (with Class Interval)

m = medianL = Lower boundary of median classN = Number of dataF = Total frequency before median classfm = Total frequency in median class

c = Class size = (Upper boundary – lower boundary)

INTERQUARTILE RANGE FOR UNGROUPED DATA

Interquartile Range of Ungrouped Data

INTERQUARTILE RANGE OF GROUPED DATA (WITH CLASS

INTERVAL)

Method 1 (using a cumulative frequency table)

Method 2 (using an ogive)

FORMULA FOR INTERQUARTILE RANGE

Cumulative Frequency

41232

48

5760

F1

𝑓 𝑄1

𝑓 𝑄3

F3

5. EXERSIZE

• For grouped data set below, calculated the interquartile range

Score 26-30 31-35 36-40 41-45 46-50Frequency 5 7 10 18 10