Unit 1 - Analysis of Data : Cumulative Frequency Curves

Question 1

How to plot a cumulative frequency graph?

Answer 1

• calculate a running total for data
• plot coordinates at the end of each group
• join points with a curve

• data treated as continuous (scores are discrete)
• data is grouped so any average is an estimation

Question 2

Quartiles

Answer 2

UQ - 75% of cum. freq.
Median - 50% of cum. freq.
LQ - 25% of cum. freq.

IQR - UQ-LQ