To test out our hunch, we need to be more precise. To do that we need to review the Normal Distribution. That's how we will compare the French and Physics tests.

Finding Yourself on the Normal Curve
Remember the normal curve. It is the shape of many measurement data distributions. The frequency of the scores tends to fall in a very specific shape in the normal distribution.

The normal curve is described by its mean (arithmetic average) and SD (average deviation of scores around the mean).

• This is the normal curve and the line in the middle is the mean (SX/N).
• Many frequency distributions in Psychology are normal.
• Each box on the graph represents a score. In our case it will be an exam score of a particular individual.
• The red arrow represents the SD.