1. Scales of Measurement …….……………………....… 2

2. Descriptives for Nominal and Ordinal Data ……....…… 7
a. The Bar Chart …………….…………………....…….. 9
b. The Pie Chart ..... …………….…………………….. .13

3.  Descriptives for Continuous Data ..………….…..….. 14
a.   The Histogram …………………………..……..….. 15
b.  The Frequency Polygon ………………………….… 19
c.  The Cumulative Frequency Polygon ……………...…. 20
d. Percentiles (Quantiles) ……………………………..... 21
e. Quantile Quantile ………………………………….… 22
f. Stem and Leaf Diagram …………………………....… 23
g. Box and Whisker Plot ……………………………..... 24

4. The Summation Notation .…………………………… 25

5. Measures of Central Tendency ……….……………… 26
a. The mode ………………………………………..….. 29 b. The mean ……..………………………….………..... 30
c. The median ………………………………….…..…... 33

6. Measures of Dispersion ………………..………….… 35
a. Variance ………………………………..…………… 36
b  Standard Deviation . …………………..…………...... 37   c. Median Absolute Deviation from Median …………... 39
d. Standard Deviation v Standard Error …… ……….…. 40  e. A Feel for Sampling Distributions ……………………. 42
f.  The Coefficient of Variation ………………………..... 45
g. The Range ……………………………………….….. 46