Unit 2: Descriptive Statistics
2.1 Types of Figures
|• Histogram: Continuous|
• Bar Graph: Categorical
• Frequency Polygon
2.2 Shapes of Curves
|• The Normal Curve|
• Right and Left Skew
|• Mean: The average|
• Median: The middle
• Mode: The highest frequency
|• Range: the difference between the highest score and the lowest score in a set of scores.|
• Interquartile Range: The range of the middle 50% (IQR = Q3 – Q1).
• Standard Deviation: The measure that indicates the degree to which the scores vary from the mean
|• 68% of scores lie within one standard deviation from the mean.|
• 95% of scores lie within two standard deviations from the mean.
• 99.7% of scores lie within three standard deviations from the mean.