Cumulative Frequency Diagrams Flashcards
Build and read cumulative frequency diagrams.
1
Q
What is cumulative frequency?
A
Cumulative means “how much so far”. Cumulative frequency counts up all of your observations “so far”.
2
Q
What goes on the x-axis of a cumulative frequency chart?
A
Your “x” values. That is, whateveaar you’re measuring.
3
Q
What goes on the y-axis of a cumulative frequency chart?
A
The cumulative frequency.
4
Q
How can you make a cumulative freqeuncy diagram from a table?
A
- Make a list of the points you’ll put on the diagram. The coordinates are (minimum,0) and then all of the (upper class limit, cumulative frequency.
- Plot the points.
- Connect the points in a smooth curve.
5
Q
How do you find the median from a cumulative frequency graph?
A
- Divide the total frequency by 2.
- Find this value on the y-axis.
- Draw a horizontal line over to the curve.
- Draw a vertical line from the curve down to the x-axis. This value is the median.
6
Q
How do you find interquartile range from a cumulative frequency diagram?
A
- Identify Q1
- Identify Q3
- IQR=Q3-Q1
7
Q
How do you find the lower quartile (Q1)?
A
- Multiply total frequency by 0.25.
- Find this value on the y-axis.
- Draw a horizontal line over to the curve.
- Draw a vertical line from the curve down to the x-axis. This value is the lower quartile.
8
Q
How do you find the upper quartile (Q3)?
A
- Multiply total frequency by 0.75.
- Find this value on the y-axis.
- Draw a horizontal line over to the curve.
- Draw a vertical line from the curve down to the x-axis. This value is the upper quartile.