Datasets can be represented in frequency tables, with a row containing the values that exist in the data and a row containing the frequency, or number of times each value appears.
The mean of frequency data can be calculated using the formula:
If we take the above
Note that fi is the frequency of the value xi, so n=i=1∑kfi is just the total number of points.
When data is continuous, we cannot have a column per possible value, as there are infinitely many.
Instead, we use a grouped frequency table to break up the data into specific intervals.
If all the intervals have equal size, then the modal class is the interval in which the most values fall.
We can also estimate the mean from grouped data as if it were a discrete frequency table using the mid-interval values, that is the average of the upper and lower bounds of each interval.
Grouped frequency tables can also be turned into histograms (aka bar graph) by drawing rectangles with base corresponding to the intervals, and heights corresponding to the frequency.
Nice work completing Frequency tables and histograms, here's a quick recap of what we covered:
Exercises checked off
Datasets can be represented in frequency tables, with a row containing the values that exist in the data and a row containing the frequency, or number of times each value appears.
The mean of frequency data can be calculated using the formula:
If we take the above
Note that fi is the frequency of the value xi, so n=i=1∑kfi is just the total number of points.
When data is continuous, we cannot have a column per possible value, as there are infinitely many.
Instead, we use a grouped frequency table to break up the data into specific intervals.
If all the intervals have equal size, then the modal class is the interval in which the most values fall.
We can also estimate the mean from grouped data as if it were a discrete frequency table using the mid-interval values, that is the average of the upper and lower bounds of each interval.
Grouped frequency tables can also be turned into histograms (aka bar graph) by drawing rectangles with base corresponding to the intervals, and heights corresponding to the frequency.
Nice work completing Frequency tables and histograms, here's a quick recap of what we covered:
Exercises checked off