Histograms

Question 1

What is a histogram?

Answer 1

A histogram is similar to a bar chart, but is used to display quantitative continuous data. Histograms take into account how densely populated groups are, show the distribution of data and can be used to calculate estimates.

Question 2

How do you calculate frequency density?

Answer 2

Freq. density = freq. / class width

Question 3

How do you plot a histogram?

Answer 3

1. Add two columns to the frequency table labelled ‘class width’ and ‘freq. density’
2. Calculate the class width for each group, upper value - lower value
3. Calculate the frequency densities (freq./class width)
4. Use the frequency density and class widths to create the axis
5. Plot bars for each group

Question 4

How do you calculate proportion from a histogram?

Answer 4

Desired group/total x 100

Question 5

How do you find the mode using a histogram?

Answer 5

• find the tallest bar
• cross the corners in an X shape