Histograms- Flashcards
What type of data are histograms used for
Continuous data
What is on the x axis of a histogram
The class widths
What is on the y axis of a histogram
Frequency
Should there be gaps between the bars in histograms
No because the scale on the x axis is continuous
When one class ends the next one starts
What can be done with a histogram
Identify the lowest or highest frequency
Estimate a frequency above or below a certain value and comment on the distribution of the data
How do you draw a frequency polygon from a histogram
Plot the midpoints if each class at the top of the bar and join them together with straight lines
What do histograms with unequal class widths have on there y axis
Frequency density
Frequency density equation
Frequency density = frequency/class width
How to estimate frequency using histograms
Frequency = frequency density x class width
What must be the same for you to compare 2 histograms
The frequency density scale and class intervals are the same on both
