There are many different types of data presentation.  Four of those types include tables, bar graphs, line graphs and pie charts.  

A table lists data in columns.  Tables can be useful if trying to show comparisons between certain types of data, such as what services each department provides.  However, tables may be less effective if trying to show a trend over time, such as how many patients entered an emergency department.  That would be better demonstrated using a line graph.

A line graph plots data points along a number line.  Line graphs can help show changes in the data over time or demonstrate trends.  A disadvantage of a line graph is that one particular data point cannot be effectively evaluated using this method.  That may be better done with a bar graph.

Bar graphs compare data at a point in time and assist the viewer in comparing different types of data.  For example, if someone would want to see what day of the week was busiest for the emergency department, that would best be illustrated by a bar graph.  A disadvantage to a bar graph is also that it does not demonstrate trends over time as well as line graph.

A pie chart may be used in a similar fashion to a bar graph.  An advantage of the pie chart is it shows the parts of a whole.  Using the emergency department example, it would show the week as a whole and the percentage of patients entering the emergency department each day of the week.  A disadvantage to a pie chart is that too many variables may make it difficult to read.