Cumulative frequency graphs are a powerful visual representation of continuous data.
The value of y at each point x on the curve represents the number of data points less than x.
We start with a grouped frequency table, and add a row for cumulative frequency, which is the number of items in an interval and all previous (lower) intervals. To plot the diagram, we make a point from each column. The x-coordinates are the upper bound of each interval, and the y-coordinates are the cumulative frequency.
Cumulative frequency diagrams can be used to find medians, quartiles, and percentiles.
In the same way that the first quartile, Q1, is the value greater than a quarter (25%) of data values, the kth percentile is the value greater than k% of the data values.
Q1: 0.25× the max
Median: 0.5× the max
Q3: 0.75× the max
kth percentile: 100k× the max.
Nice work completing Cumulative frequency, here's a quick recap of what we covered:
Exercises checked off
Cumulative frequency graphs are a powerful visual representation of continuous data.
The value of y at each point x on the curve represents the number of data points less than x.
We start with a grouped frequency table, and add a row for cumulative frequency, which is the number of items in an interval and all previous (lower) intervals. To plot the diagram, we make a point from each column. The x-coordinates are the upper bound of each interval, and the y-coordinates are the cumulative frequency.
Cumulative frequency diagrams can be used to find medians, quartiles, and percentiles.
In the same way that the first quartile, Q1, is the value greater than a quarter (25%) of data values, the kth percentile is the value greater than k% of the data values.
Q1: 0.25× the max
Median: 0.5× the max
Q3: 0.75× the max
kth percentile: 100k× the max.
Nice work completing Cumulative frequency, here's a quick recap of what we covered:
Exercises checked off