Cumulative Frequency Diagrams

Question 1

What is cumulative frequency?

Answer 1

Cumulative means “how much so far”. Cumulative frequency counts up all of your observations “so far”.

Question 2

What goes on the x-axis of a cumulative frequency chart?

Answer 2

Your “x” values. That is, whateveaar you’re measuring.

Question 3

What goes on the y-axis of a cumulative frequency chart?

Answer 3

The cumulative frequency.

Question 4

How can you make a cumulative freqeuncy diagram from a table?

Answer 4

1. 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.
2. Plot the points.
3. Connect the points in a smooth curve.

Question 5

How do you find the median from a cumulative frequency graph?

Answer 5

1. Divide the total frequency by 2.
2. Find this value on the y-axis.
3. Draw a horizontal line over to the curve.
4. Draw a vertical line from the curve down to the x-axis. This value is the median.

Question 6

How do you find interquartile range from a cumulative frequency diagram?

Answer 6

1. Identify Q₁
2. Identify Q₃
3. IQR=Q₃-Q₁

Question 7

How do you find the lower quartile (Q₁)?

Answer 7

1. Multiply total frequency by 0.25.
2. Find this value on the y-axis.
3. Draw a horizontal line over to the curve.
4. Draw a vertical line from the curve down to the x-axis. This value is the lower quartile.

Question 8

How do you find the upper quartile (Q₃)?

Answer 8

1. Multiply total frequency by 0.75.
2. Find this value on the y-axis.
3. Draw a horizontal line over to the curve.
4. Draw a vertical line from the curve down to the x-axis. This value is the upper quartile.