Statistical and Graphical Example

Example 1: Grade distribution

 

Below is a histogram of grades from the first exam from Principles of Finance at Tarleton State University for spring 2011. As the histogram shows, the grades are approximately normally distributed. The table following the graphic provides some summary statistics. We see the average grade was 67.60 with a standard deviation of 16.75. This means we see about 68% of the grades falling with in ±16.75 points (±1 standard deviation) of the mean. Because the distribution is approximately normal, the median and mean grades are not far apart. 

 

 

return to top | previous page | next page