The spreadsheet grades.xls contains grade distributions for various mathematics classes at Texas Tech over the last 10 years.

There are natural questions which arise:

• Does this data show any evidence for grade inflation occurring over that time frame?
• Does this data show that the grade distributions are significantly different between courses?
• Within a given course are the grade distributions from summer term sessions different from the grade distributions for regular sessions?

Of course, a rigorous response to either question would require a statistical analysis. However, graphical information could support the justification for conducting a formal statistical analysis. Respond to the above questions by providing the following graphical information.

• Choose two the large courses (for which the overall registration has been at least 10,000). Provide for those two courses charts which show the course GPA. (Consider only the regular semester GPA.) Is there any change (with time)? Is it "grade inflation"?
• Choose two the large courses (for which the overall registration has been at least 10,000). Provide for those two courses charts which show the course GPA contrasting regular sessions to summer terms.
• Choose two the large courses (for which the overall registration has been at least 10,000). Provide for these two courses charts which contrast grade distributions (A,B,C,D,all others) for regular sessions to summer terms.