Depending on the data type, we can use different types of display. When dealing with categorical (nominal) data we often use a bar chart. A bar chart is used to represent categorical (nominal) data.
Another means of displaying categorical data is to use a divided bar chart. These are also called stacked bar charts or segmented bar charts and are really sector (pie) graphs presented in a rectangular format.
We can also draw what is known as a percentaged segmented bar chart. In this case, the height of the bar is 100%.
We should not use a bar chart when dealing with numerical data. Instead, when we have discrete data we an draw a frequency diagram. A frequency diagram is used to represent numerical (discrete) data whether it is discrete or grouped.
When we have a relatively small discrete data set we often represent it as a stemplot (or stem-and-leaf plot). This type of display preserves all of the information collected in the data set and gives a useful pictorial representation of the data set as well. In a stem-and-leaf diagram, the leaf is the units value of the individual datum value and the stem is the other part of the number. The advantage with a stem-and-leaf diagram is that it does not lose any of the detail in the data.
When dealing with continuous numerical data we often use a frequency histogram. A histogram is used to represent numerical (continuous) data.
Continuous data can also be represented in a cumulative frequency curve which can be used to indicate the number of data values less than a particular value.
When we have a continuous data set recorded in class intervals we can draw what is called a cumulative frequency diagram.
Relative frequency and percentage frequency columns can be added to frequency tables. Relative frequency is found by dividing the frequency by the total frequency, and we multiply this value by 100 to obtain the percentage relative frequency.
Which of the following statements is incorrect: A A histogram is used for numerical (continuous) data B A bar chart is used for categorical (nominal) data C A histogram is used for numerical (discrete) data D A frequency diagram can be used for numerical (discrete or grouped discrete) data E A bar chart should never be used for numerical data